2,6-disubstituted pyridine derivative

ABSTRACT

The present invention relates to a pyridine derivative of formula (1) wherein R 1  is optionally-substituted C 1-6  alkyl, optionally-substituted C 3-10  cycloalkyl, or optionally-substituted 5- to 10-membered saturated or partially-unsaturated heterocyclyl; R 2  is halogen atom, cyano, C 1-6  alkyl which may be optionally substituted with 1 to 3 the same or different halogen atoms, C 1-6  alkoxy which may be optionally substituted with 1 to 3 the same or different halogen atoms, or amino which may be optionally substituted with 1 to 2 the same or different C 1-6  alkyl; and the bind with broken line is single or double bond, or a pharmaceutically acceptable salt thereof, which is useful as a medicament for treating symptoms in anxiety-related disorder.

TECHNICAL FIELD

The present invention relates to a 2,6-disubstituted pyridine derivativeor a pharmaceutically acceptable salt thereof which has dual agonism forserotonin 5-HT_(1A) receptor and dopamine D₄ receptor; and a medicamentfor treating symptoms of anxiety-related disorder, comprising thederivative as an active ingredient.

BACKGROUND ART

Serotonin (5-hydroxytryptamine: 5-HT) is known as one of mainneurotransmitters in central nervous system, and it is also known thatserotonin is involved in various brain functions such as emotionalreaction and cognitive function. Serotonin 5-HT_(1A) receptor(hereinafter, referred to as “5-HT_(1A), receptor”) which is one of 5-HTreceptor subtypes is highly expressed in cerebral cortex, hippocampus,raphe nucleus, amygdala, and the like. It is thought that anxiety orfear memory formation can be caused by the overactive of amygdala, andthe activity of amygdala can be suppressed by stimulating 5-HT_(1A)receptor. Thus, it is considered that a 5-HT_(1A) agonist cansuppressively control the neural circuit of anxiety/fear (Non-PatentLiterature 1).

In addition, it is known that dopamine D₄ receptor (hereinafter,referred to as “D₄ receptor”) which is one of dopamine receptor subtypescan also control the neural circuit of anxiety/fear formation.Specifically, D₄ receptor is present a lot in the medial prefrontalcortex which is a part of cerebral cortex, and the above-mentionedamygdala which is a responsible moiety for anxious formation also has amutual neuron-connection to the medial prefrontal cortex. Thus, it issuggested that the stimulation to D₄ receptor can suppressively controlthe activity of amygdala to act on the control of anxiety/fear(Non-Patent Literature 2).

From the above-mentioned pharmacological viewpoint, it is expected thata drug having more potent and extensive antianxiety than existing5-HT_(1A) agonists can be created, if stimulating simultaneously both of5-HT_(1A) receptor and D₄ receptor to control the neural circuitfunction involved in anxiety from plural directions. However, anyspecific drugs having selective dual agonism for both the two receptorshave not been reported.

Patent Literature 1 discloses pyridylpiperidine derivatives and the likewhich have D₄ receptor agonism. Patent Literature 2 disclosespyridylpiperazine derivatives and the like which are useful as anantianxiety drug.

PRIOR ART Patent Reference

-   [Patent Literature 1] WO 2014/192868-   [Patent Literature 2] JP S59-29665 A

Non-Patent Reference

-   [Non-Patent Literature 1] Psychopharmacology 2014, 231(4), 623-36-   [Non-Patent Literature 2] The Showa University Journal of    pharmaceutical sciences, Vol. 1, No. 1, 2010, pp. 17-28.

SUMMARY OF INVENTION Technical Problem

The purpose of the present invention may be to provide a new compounduseful as a medicament for treating symptoms of anxiety-relateddisorder, which has dual agonism for 5-HT_(1A) receptor and D₄ receptor.

Solution to Problem

The present inventors have extensively studied to reach the abovepurpose, and then have found that a compound of formula (1) shown belowor a pharmaceutically acceptable salt thereof (hereinafter, it may bereferred to as “the present compound”) has dual agonism for 5-HT_(1A)receptor and D₄ receptor. Based upon the new findings, the presentinvention has been completed.

The present invention can show as follows.

(Item 1)

A compound of formula (1):

or a pharmaceutically acceptable salt thereof, wherein

-   -   R¹ is optionally-substituted C₁₋₆ alkyl, optionally-substituted        C₃₋₁₀ cycloalkyl, or optionally-substituted 5- to 10-membered        saturated or partially-unsaturated heterocyclyl group;    -   R² is halogen atom, cyano, C₁₋₆ alkyl which may be optionally        substituted with 1 to 3 the same or different halogen atoms,        C₁₋₆ alkoxy which may be optionally substituted with 1 to 3 the        same or different halogen atoms, or amino which may be        optionally substituted with 1 or 2 the same or different C₁₋₆        alkyl groups; and the bond accompanied with broken line is        single bond or double bond.

(Item 2)

The compound of Item 1 or a pharmaceutically acceptable salt thereof,wherein

-   -   R¹ is    -   (1) C₁₋₆ alkyl which may be optionally substituted with 1 to 3        the same or different substituents selected from the group        consisting of halogen atom, hydroxy, C₃₋₇ cycloalkyl, and C₁₋₆        alkoxy,    -   (2) C₃₋₁₀ cycloalkyl which may be optionally substituted with 1        to 4 the same or different substituents selected from the group        consisting of halogen atom, hydroxy, cyano, C₁₋₆ alkyl which may        be optionally substituted with 1 to 3 the same or different        halogen atom or C₁₋₆ alkoxy, C₁₋₆ alkoxy which may be optionally        substituted with 1 to 3 the same or different halogen atom or        C₁₋₆ alkoxy, and amino which may be optionally substituted with        1 or 2 the same or different C₁₋₆ alkyl, or    -   (3) 5- to 10-membered saturated or partially-unsaturated        heterocyclyl group which may be optionally substituted with 1 to        4 the same or different substituents selected from the group        consisting of halogen atom, hydroxy, cyano, C₁₋₆ alkyl which may        be optionally substituted with 1 to 3 the same or different        halogen atom or C₁₋₆ alkoxy, C₁₋₆ alkoxy which may be optionally        substituted with 1 to 3 the same or different halogen atom or        C₁₋₆ alkoxy, and amino which may be optionally substituted with        1 or 2 the same or different C₁₋₆ alkyl.

(Item 3)

The compound of Item 1 or 2, or a pharmaceutically acceptable saltthereof, wherein

-   -   R¹ is    -   (1) C₃₋₇ cycloalkyl which may be optionally substituted with 1        to 4 the same or different substituents selected from the group        consisting of halogen atom, and C₁₋₆ alkyl which may be        optionally substituted with 1 to 3 the same or different halogen        atom or C₁₋₆ alkoxy, or    -   (2) 5- or 6-membered saturated or partially-unsaturated        heterocyclyl group which may be optionally substituted with 1 to        4 the same or different substituents selected from the group        consisting of halogen atom, and C₁₋₆ alkyl which may be        optionally substituted with 1 to 3 the same or different halogen        atom or C₁₋₆ alkoxy.

(Item 4)

The compound of any one of Items 1 to 3, or a pharmaceuticallyacceptable salt thereof, wherein R¹ is C₃₋₇ cycloalkyl which may beoptionally substituted with 1 to 4 fluorine atoms, or 5- or 6-memberedsaturated or partially-unsaturated heterocyclyl group which may beoptionally substituted with 1 to 4 fluorine atoms.

(Item 5)

The compound of any one of Items 1 to 4, or a pharmaceuticallyacceptable salt thereof, wherein R¹ is cyclohexyl which may beoptionally substituted with 1 to 4 fluorine atoms, tetrahydropyranyl,tetrahydrofuryl, dihydropyranyl, or dihydrofuryl.

(Item 6)

The compound of any one of Items 1 to 5, or a pharmaceuticallyacceptable salt thereof, wherein R¹ is difluorocyclohexyl, ortetrahydropyranyl.

(Item 7)

The compound of any one of Items 1 to 6, or a pharmaceuticallyacceptable salt thereof, wherein R² is halogen atom, or C₁₋₆ alkyl whichmay be optionally substituted with 1 to 3 the same or different halogenatoms.

(Item 8)

The compound of any one of Items 1 to 7, or a pharmaceuticallyacceptable salt thereof, wherein R² is C₁₋₄ alkyl which may beoptionally substituted with 1 to 3 fluorine atoms.

(Item 9)

The compound of any one of Items 1 to 8, or a pharmaceuticallyacceptable salt thereof, wherein the bond accompanied with broken lineis single bond.

(Item 10)

The compound of Item 1 selected from the following compounds, or apharmaceutically acceptable salt thereof,

-   4,4-difluoro-N-(2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)cyclohexane-carboxamide    (Example 1),-   N-{2-[4-(6-methylpyridin-2-yl)piperidin-1-yl]ethyl}-tetrahydro-2H-pyran-4-carboxamide    (Example 8),-   2,2-dimethyl-N-(2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)propanamide    (Example 9), and-   N-(2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)-tetrahydro-2H-pyran-4-carboxamide    (Example 11).

(Item 11)

The compound of Item 1 selected from the following compounds, or apharmaceutically acceptable salt thereof,

-   4,4-difluoro-N-(2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)cyclohexane-carboxamide    (Example 1),-   N-{2-[4-(6-methylpyridin-2-yl)piperidin-1-yl]ethyl}-tetrahydro-2H-pyran-4-carboxamide    (Example 8), and-   N-(2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)-tetrahydro-2H-pyran-4-carboxamide    (Example 11).

(Item 12)

The compound of Item 1 of the following compound, or a pharmaceuticallyacceptable salt thereof,

-   4,4-difluoro-N-(2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)cyclohexane-carboxamide    (Example 1).

(Item 13)

The compound of Item 1 of the following compound, or a pharmaceuticallyacceptable salt thereof,

-   N-{2-[4-(6-methylpyridin-2-yl)piperidin-1-yl]ethyl}-tetrahydro-2H-pyran-4-carboxamide    (Example 8).

(Item 14)

The compound of Item 1 of the following compound, or a pharmaceuticallyacceptable salt thereof,

-   2,2-dimethyl-N-(2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)propanamide    (Example 9).

(Item 15)

The compound of Item 1 of the following compound, or a pharmaceuticallyacceptable salt thereof,

-   N-(2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)-tetrahydro-2H-pyran-4-carboxamide    (Example 11).

(Item 16)

A medicament comprising the compound of any one of Items 1 to 15 or apharmaceutically acceptable salt thereof as an active ingredient.

(Item 17)

A medicament for treating generalized anxiety disorder, majordepression, obsessive-compulsive disorder, Parkinson's disease, Rettsyndrome, attention-deficit hyperactivity disorder, autism spectrumdisorder, or dementia, comprising the compound of any one of Items 1 to15 or a pharmaceutically acceptable salt thereof as an activeingredient.

(Item 18)

A method for treating generalized anxiety disorder, major depression,obsessive-compulsive disorder, Parkinson's disease, Rett syndrome,attention-deficit hyperactivity disorder, autism spectrum disorder, ordementia, comprising administering a therapeutically effective amount ofthe compound of any one of Items 1 to 15 or a pharmaceuticallyacceptable salt thereof to a patient in need thereof.

(Item 19)

Use of the compound of any one of Items 1 to 15 or a pharmaceuticallyacceptable salt thereof, in the preparation of a medicament for treatinggeneralized anxiety disorder, major depression, obsessive-compulsivedisorder, Parkinson's disease, Rett syndrome, attention-deficithyperactivity disorder, autism spectrum disorder, or dementia.

(Item 20)

The compound of any one of Items 1 to 15 or a pharmaceuticallyacceptable salt thereof, for use in the treatment of generalized anxietydisorder, major depression, obsessive-compulsive disorder, Parkinson'sdisease, Rett syndrome, attention-deficit hyperactivity disorder, autismspectrum disorder, or dementia.

(Item 21)

A medicament comprising the compound of any one of Items 1 to 15 or apharmaceutically acceptable salt thereof, and at least one othermedicament selected from drugs classified as an antianxiety drug or anantidepressant drug.

(Item 22)

A medicament for treating generalized anxiety disorder, majordepression, obsessive-compulsive disorder, Parkinson's disease, Rettsyndrome, attention-deficit hyperactivity disorder, autism spectrumdisorder, or dementia, comprising the compound of any one of Items 1 to15 or a pharmaceutically acceptable salt thereof, which is used incombination with at least one other medicament selected from drugsclassified as an antianxiety drug or an antidepressant drug.

(Item 23)

The medicament of Item 21 or 22, wherein the antianxiety drug is aselective serotonin reuptake inhibitor.

(Item 24)

The medicament of Item 23, wherein the selective serotonin reuptakeinhibitor is at least one drug selected from the group consisting ofsertraline, escitalopram, fluvoxamine, fuoxetine, paroxetine,clomipramine, and pharmaceutically acceptable salts thereof.

(Item 25)

The medicament of any one of Items 21 to 24, wherein the antidepressantdrug is a serotonin reuptake inhibitor.

(Item 26)

The medicament of Item 25, wherein the serotonin reuptake inhibitor isat least one drug selected from the group consisting of milnacipran,duloxetine, venlafaxine, amoxapine, clomipramine, nortriptyline,imipramine, vortioxetine, and pharmaceutically acceptable salts thereof.

Effect of the Invention

The present compound has dual agonism for 5-HT_(1A) receptor and D₄receptor. In a preferred embodiment, the present compound has a goodmetabolic stability, provides a long disappearance half-life (T_(1/2)),and exhibits a weak inhibitory action to a different GPCR, dopamine D₂receptor (hereinafter, referred to as “D₂ receptor”) and hERG channel.Thus, some preferred compounds of the present invention are useful as amedicament for treating symptoms in anxiety-related disorder, which hasa long persistence effect in human body and a high safety.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows the results of the compounds of Examples 1, 8, and 11 inthe contextual fear conditioning test (Test 6).

FIG. 2 shows the results of the compounds of Examples 1 and 11 in themarble-burying behavior test (Test 7).

FIG. 3 shows the results of the combination of the compound of Example 1and escitalopram, and the combination of the compound of Example 11 andescitalopram in marble-burying behavior test (Test 7).

FIG. 4 shows the results of the compounds of Examples 1 and 11 in theforced swimming test (Test 8).

FIG. 5 shows the results of the compound of Example 11, and thecombination of the compound of Example 11 and sertraline in themicrodialysis test (Test 9).

DESCRIPTION OF EMBODIMENTS

Hereinafter, the present invention is described in detail. In thedescription, the number of carbon atoms in the definition of“substituents” can indicates, for example, “C₁₋₆”. The specificdefinition “C₁₋₆ alkyl” means an alkyl group having 1 to 6 carbon atoms.

The “halogen atom” includes, for example, fluorine atom, chlorine atom,bromine atom, and iodine atom.

The “C₁₋₆ alkyl” used herein means straight or branched chain saturatedhydrocarbon group having 1 to 6 carbon atoms. Preferably, it is “C₁₋₄alkyl group”. The “C₁₋₆ alkyl group” includes, for example, methyl,ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl,pentyl, isopentyl, neopentyl, 1-ethylpropyl, hexyl, isohexyl,1,1-dimethylbutyl, 2,2-dimethylbutyl, 3,3-dimethylbutyl, and2-ethylbutyl.

The “C₃₋₁₀ cycloalkyl” used herein means 3- to 10-membered saturated orpartially-unsaturated mono-cyclic or multiple-cyclic hydrocarbon group.The “partially-unsaturated” means a state wherein the ring structure hasone or some unsaturated bond(s), but it does not become a completelyunsaturated aromatic ring (hereinafter, the same definition of“partially-unsaturated” applies). Preferably, it is “C₃₋₇ cycloalkyl”.The “C₃₋₁₀ cycloalkyl” includes, for example, cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cyclopentenyl, and cyclohexenyl.

The “C₁₋₆ alkyl” moiety in the “C₁₋₆ alkoxy” is as defined in theaforementioned “C₁₋₆ alkyl”. Preferably, it is “C₁₋₄ alkoxy”. The “C₁₋₆alkoxy” includes, for example, methoxy, ethoxy, propoxy, isopropoxy,butoxy, isobutoxy, sec-butoxy, and tert-butoxy.

The “5- to 10-membered saturated or partially-unsaturated heterocyclylgroup” includes, for example, 5- to 10-membered saturated orpartially-unsaturated mono-cyclic or multiple-cyclic heterocyclyl groupwhich has 1 to 3 the same or different atoms selected from the groupconsisting nitrogen atom, oxygen atom, and sulfur atom. Specifically, itincludes dihydropyranyl, tetrahydropyranyl, dihydrofuryl,tetrahydrofuryl, aziridinyl, azetidinyl, pyrrolidinyl, imidazolidinyl,piperidinyl, piperazinyl, azepanyl, morpholinyl, and thiomorpholinyl.The binding site of each group may be any atom of the carbon atoms andthe nitrogen atoms which compose the ring.

Preferably, it includes 5- or 6-membered saturated heterocyclyl group.More preferably, it includes the following formulae (11), (12), (13),and (14).

Wherein the binding bar crossing each ring means that the “binding bar”attaches at a substitutable site of the ring. More preferably, it is thegroup of formula (11).

The substituent in the “optionally-substituted C₁₋₆ alkyl” includes, forexample, halogen atom, hydroxy, C₃₋₇ cycloalkyl, and C₁₋₆ alkoxy,preferably fluorine atom.

The substituent in the “optionally-substituted C₃₋₁₀ cycloalkyl”, or the“optionally-substituted 5- to 10-membered saturated orpartially-unsaturated heterocyclyl group” includes, for example,

-   -   (a) halogen atom,    -   (b) hydroxy,    -   (c) cyano,    -   (d) C₁₋₆ alkyl which may be optionally substituted with 1 to 3        the same or different halogen atom or C₁₋₆ alkoxy,    -   (e) C₁₋₆ alkoxy which may be optionally substituted with 1 to 3        the same or different halogen atom or C₁₋₆ alkoxy, and    -   (f) amino which may be optionally substituted with 1 or 2 the        same or different C₁₋₆ alkyl.

Preferably, it is halogen atom, or C₁₋₆ alkyl which may be optionallysubstituted with 1 to 3 the same or different halogen atom or C₁₋₆alkoxy; more preferably fluorine atom.

In the present compound of formula (1), the bond accompanied with brokenline, R¹, and R² are preferably the following ones, but should not belimited thereto.

The bond accompanied with broken line is preferably single bond.

R¹ includes, preferably,

(1) C₃₋₇ cycloalkyl which may be optionally substituted with 1 to 4 thesame or different substituents selected from the group consisting ofhalogen atom, and C₁₋₆ alkyl which may be optionally substituted with 1to 3 the same or different halogen atom or C₁₋₆ alkoxy, and

(2) 5- or 6-membered saturated or partially-unsaturated heterocyclylgroup which may be optionally substituted with 1 to 4 the same ordifferent substituents selected from the group consisting of halogenatom, and C₁₋₆ alkyl which may be optionally substituted with 1 to 3 thesame or different halogen atom or C₁₋₆ alkoxy.

R¹ includes, more preferably, C₃₋₇ cycloalkyl which may be optionallysubstituted with 1 to 4 fluorine atoms, and 5- or 6-membered saturatedor partially-unsaturated heterocyclyl group which may be optionallysubstituted with 1 to 4 fluorine atoms. Even more preferably, R¹includes cyclohexyl which may be optionally substituted with 1 to 4fluorine atoms, tetrahydropyranyl, tetrahydrofuryl, dihydropyranyl, anddihydrofuryl. More preferably, R¹ includes difluorocyclohexyl, andtetrahydropyranyl. More preferably, R¹ includes 4,4-difluorocyclohexyl,and 4-tetrahydropyranyl.

R² includes, preferably, halogen atom, and C₁₋₆ alkyl which may beoptionally substituted with 1 to 3 the same or different halogen atoms.More preferably, R² includes C₁₋₄ alkyl which may be optionallysubstituted with 1 to 3 fluorine atoms; even more preferably, R²includes methyl which may be optionally substituted with 1 to 3 fluorineatoms.

The compound of formula (1) can exist as a tautomer thereof. Thus, thecompound of the present invention also includes a tautomer of compound(1).

The compound of formula (1) can have at least one chiral carbon atom.Thus, the compound of the present invention also includes a racemate ofcompound (1) as well as an optically active compound (1). When thecompound of formula (1) has two or more chiral carbon atoms, thecompound can be a stereoisomeric form. Thus, the compound of the presentinvention also includes a stereoisomer thereof and a mixture ofstereoisomers.

In addition, the compound of formula (1) in which any one or more 1Hatoms are replaced by ²H(D) atoms (deuterium form) is also within thescope of the present invention of formula (1).

The compound of formula (1) and a pharmaceutically acceptable saltthereof may be also in a form of hydrate and/or solvate, thus thecompound of the present invention encompasses such hydrate thereof andsolvate thereof such as ethanolate. In addition, the compound of thepresent invention also includes various embodiments of its crystal form.

The pharmaceutically acceptable salt of the compound of formula (1),when the compound has an acidic group, includes, for example, alkalimetal salts such as sodium salt and potassium salt; alkaline earth metalsalts such as calcium salt and magnesium salt; inorganic metal saltssuch as zinc salt; and organic base salts such as triethylamine,triethanolamine, tri(hydroxymethyl)aminomethane, and amino acid.

The pharmaceutically acceptable salt of the compound of formula (1),when the compound has a basic group, includes, for example, inorganicacid salts such as hydrochloride, hydrobromide, sulfate, phosphate, andnitrate; and organic acid salts such as acetate, propionate, succinate,lactate, malate, tartrate, citrate, maleate, fumarate, methanesulfonate,p-toluenesulfonate, benzenesulfonate, and ascorbate.

Hereinafter, the processes to prepare the present compound of formula(1) are explained along with examples, but the present invention shouldnot be limited thereto.

Preparation Process

The compounds of the present invention can be prepared by means of thepreparation processes mentioned below, or processes combined with knownprocesses.

Each compound appearing in the following schemes may be also in its saltform, and such salts may include, for example, the corresponding saltsexemplified as the salt of the compound of formula (1). The reactionsmentioned below are just examples, thus the compounds of the presentinvention may be prepared by other means based on the knowledge of askilled person in organic synthesis.

If there is a function group that needs to be protected in thepreparation processes mentioned below, the function group may beprotected as appropriate and then deprotected after completing thereaction or the reaction sequences, even though the use of anyprotecting groups is not specifically indicated.

The protecting group used herein includes, for example, generalprotecting groups described in T. W. Greene and P. G. M. Wuts,“Protective Groups in Organic Synthesis”, 3rd Ed., John Wiley and Sons,inc., New York (1999); in more detail, it includes, for example,benzyloxycarbonyl, tert-butoxycarbonyl, acetyl, and benzyl, for aminogroup; and trialkylsilyl, acetyl, and benzyl, for hydroxy group. Theprotection and deprotection can be carried out by conventional means inorganic synthesis chemistry (for example, the methods described in T. W.Greene and P. G. M. Wuts, “Protective Groups in Organic Synthesis”, 3rdEd., John Wiley and Sons, inc., New York (1999)), or similar means tothem.

Preparation Process 1

The compound of formula (1) can be prepared, for example, by thefollowing process.

Wherein R¹ and R² are as defined in the above Item 1; the bondaccompanied with broken line is single bond or double bond; LG isleaving group such as iodine atom, bromine atom, chlorine atom, andsubstituted sulfonyl (e.g. methanesulfonyl, p-toluenesulfonyl, etc.);Pro is a protective group for amino group.

Step 1-1: Preparation Step of Compound (1-3)

Compound (1-3) can be prepared by reacting Compound (1-1) and Compound(1-2) in a suitable solvent in the presence or absence of a base. Thestep may be carried out in the presence of a base if necessary, or inthe presence of a phase-transfer catalyst if necessary. The reactiontemperature is generally about −20° C. to boiling point of a solventused herein. The reaction time depends on the reaction condition such asthe reaction temperature, the condensing agent used herein, the startingmaterial, and the reaction solvent, which is generally about 10 minutesto 48 hours.

Compound (1-1) can be got as a marketed product or can be prepared by aknown synthetic method (for example, WO 2014/192868).

Compound (1-2) can be got as a marketed product or can be prepared by aknown synthetic method (for example, J. Org. Chem. 1988, 53, 2226-2232).

The base used herein includes, for example, organic bases such astriethylamine, diisopropylethylamine, and pyridine; inorganic bases suchas potassium carbonate, sodium carbonate, cesium carbonate, potassiumbicarbonate, sodium bicarbonate, potassium dihydrogenphosphate,dipotassium hydrogenphosphate, potassium phosphate, sodiumdihydrogenphosphate, disodium hydrogenphosphate, sodium phosphate,potassium hydroxide, sodium hydroxide, and sodium hydride; and metallicalkoxides such as sodium methoxide and potassium tert-butoxide.

The phase-transfer catalyst used herein includes, for example,tetrabutylammonium hydrogen sulfate.

The inert solvent used herein includes, for example, halogenatedsolvents such as chloroform and dichloromethane; aromatic hydrocarbonssuch as benzene and toluene; ether solvents such as diethyl ether,tetrahydrofuran (THF), and 1,4-dioxane; lower alcohol solvents such asmethanol, ethanol, and 2-propanol; aprotic polar solvents such asacetonitrile, acetone, methylethylketone, dimethylformamide,N-methyl-2-pyrrolidinone, and dimethylsulfoxide; and mixture solventsthereof.

Step 1-2: Preparation Step of Compound (1-4)

Compound (1-4) can be prepared by removing the protective group foramino group (Pro) in Compound (1-3) in a known manner (for example,Protective Groups in Organic Synthesis, 3rd Ed. edited by Theodora W.Green, Peter G. M. Wuts, issued by John Wiley & Sons Inc., in 1999).

Step 1-3: Preparation Step of Compound (1)

Compound (1) can be prepared by reacting Compound (1-4) with thecarboxylic compound of formula (1-5) in the presence of a condensingagent in an inert solvent. The reaction may be carried out further inthe presence of a base. The reaction temperature is generally about −20°C. to boiling point of a solvent used herein. The reaction time dependson the reaction condition such as the reaction temperature, thecondensing agent used herein, the starting material, and the reactionsolvent, which is generally about 10 minutes to 48 hours.

Compound (1) can be also prepared by reacting Compound (1-4) with anacid halide or acid anhydride derived from Compound (1-5) in thepresence of a base in an inert solvent. The reaction temperature isgenerally about −20° C. to boiling point of a solvent used herein. Thereaction time depends on the reaction condition such as the reactiontemperature, the condensing agent used herein, the starting material,and the reaction solvent, which is generally about 10 minutes to 48hours.

The condensing agent used herein includes, for example,dicyclohexylcarbodiimide (DCC), diisopropylcarbodiimide (DIPC),1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (WSC),benzotriazol-1-yl-tris(dimethylamino)phosphonium hexafluorophosphate(BOP), diphenylphosphonylazide (DPPA), N,N-carbonyldiimidazole (CDI),and benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate(HBTU). If necessary, an additive such as N-hydroxysuccinimide (HOSu),1-hydroxybenzotriazole (HOBt), and3-hydroxy-4-oxo-3,4-dihydro-1,2,3-benzotriazine (HOOBt) may be added tothe reaction.

The base used herein includes, for example, organic bases such astriethylamine, diisopropylethylamine, and pyridine; inorganic bases suchas potassium carbonate, sodium carbonate, cesium carbonate, potassiumbicarbonate, sodium bicarbonate, potassium dihydrogenphosphate,dipotassium hydrogenphosphate, potassium phosphate, sodiumdihydrogenphosphate, disodium hydrogenphosphate, sodium phosphate,potassium hydroxide, sodium hydroxide, and sodium hydride; and metallicalkoxides such as sodium methoxide and potassium tert-butoxide.

The inert solvent used herein includes, for example, halogenatedsolvents such as chloroform and dichloromethane; aromatic hydrocarbonssuch as benzene and toluene; ether solvents such as diethyl ether,tetrahydrofuran (THF), and 1,4-dioxane; aprotic polar solvents such asacetonitrile, acetone, methylethylketone, dimethylformamide,N-methyl-2-pyrrolidinone, and dimethylsulfoxide; basic solvents such aspyridine; and mixture solvents thereof.

Preparation Process 2

The compound of formula (1-1b) can be prepared from the compound offormula (1-1a) by the following process.

Wherein R² is as defined in the above Item 1.

Step 2: Preparation Step of Compound (1-1b)

Compound (1-1b) can be prepared by hydrogenating Compound (1-1a) underpressureless or pressured hydrogen atmosphere in a suitable inertsolvent. The catalyst used in the present reduction reaction includes,for example, palladium catalyst such as palladium carbon, rhodiumcatalyst such as rhodium carbon, platinum catalyst such as platinumcarbon, and ruthenium catalyst such as ruthenium carbon. The reactiontemperature is generally between 0° C. and 50° C. The reaction timedepends on the reaction condition such as the reaction temperature, thecatalyst used herein, the starting material, and the reaction solvent,which is generally about 10 minutes to 48 hours.

The inert solvent used herein includes, for example, ester solvents suchas ethyl acetate; aromatic hydrocarbons such as benzene and toluene;ether solvents such as diethyl ether, tetrahydrofuran, 1,4-dioxane, and1,2-dimethoxyethane; alcohol solvents such as methanol, ethanol, and2-propanol; aprotic polar solvents such as dimethylformamide,N-methyl-2-pyrrolidinone, and dimethylsulfoxide; and mixture solventsthereof.

The other compounds of formula (1-1) can be got as a marketed product orcan be prepared by a known synthetic method or a similar method thereof.

Preparation Process 3

The compound of formula (1-3b) can be also prepared from the compound(1-3a) by the following process.

Wherein R² is as defined in the above Item 1; Pro is a protective groupfor amino group.

Step 3: Preparation Step of Compound (1-3b)

Compound (1-3b) can be prepared by hydrogenating Compound (1-3a) underpressureless or pressured hydrogen atmosphere in a suitable inertsolvent. The catalyst used in the present reduction reaction includes,for example, palladium catalyst such as palladium carbon, rhodiumcatalyst such as rhodium carbon, platinum catalyst such as platinumcarbon, and ruthenium catalyst such as ruthenium carbon. The reactiontemperature is generally between 0° C. and 50° C. The reaction timedepends on the reaction condition such as the reaction temperature, thecatalyst used herein, the starting material, and the reaction solvent,which is generally about 10 minutes to 48 hours.

The inert solvent used herein includes, for example, ester solvents suchas ethyl acetate; aromatic hydrocarbons such as benzene and toluene;ether solvents such as diethyl ether, tetrahydrofuran, 1,4-dioxane, and1,2-dimethoxyethane; alcohol solvents such as methanol, ethanol, and2-propanol; aprotic polar solvents such as dimethylformamide,N-methyl-2-pyrrolidinone, and dimethylsulfoxide; and mixture solventsthereof.

The present compound having a desired functional group at a desiredposition can be prepared by suitably combining the above preparationprocesses. The isolation and purification of each intermediate orproduct in the above preparation processes can be carried out byconventional manners in organic synthesis, for example, by suitablycombining filtration, extraction, washing, drying, concentration,crystallization, various chromatography, etc.

Or, some intermediates may be sometimes used in the next step withoutpurification.

Some starting compounds or intermediates in the above preparationprocesses can exist in a salt form such as hydrochloride, but can beused as free form thereof. When starting compounds or intermediates thatare in salt form need to be used or obtained as free form thereof, theycan be transformed to free forms thereof by dissolving or suspendingthem in an appropriate solvent and neutralizing the solution orsuspension with a base such as aqueous sodium bicarbonate.

Some of the compound of formula (1) or a pharmaceutically acceptablesalt thereof can exist as isomers such as tautomer (for example,keto-enol form), regioisomer, geometrical isomer, and optical isomer.The present invention encompasses every possible isomer including theabove, and a mixture thereof which has various mixture proportions. And,optical isomers thereof can be resolved by a known manner such aschromatography with an optically-active column and fractionalcrystallization at a suitable step in the above-mentioned preparationprocesses. And, an optically-active starting material can be also usedfor this purpose.

In order to obtain the compound of formula (1) as a salt thereof, whenthe product is a salt of the compound of formula (1), the product shouldbe directly purified; or when the product is in free form of thecompound of formula (1), the product should be dissolved or suspended inan appropriate solvent and then an acid or a base should be addedthereto to form a salt thereof. And, some of compound (1) or apharmaceutically acceptable salt thereof can exist as a hydrate thereofor a solvate thereof with various solvents, which are also included inthe present invention.

5-HT_(1A) receptor is highly expressed in cerebral cortex, hippocampus,raphe nucleus, amygdala, and the like. It is considered that anxiety orfear memory formation can be caused by the overactive of amygdala. Theactivity of amygdala can be suppressed by stimulating 5-HT_(1A)receptor, thus it is considered that a 5-HT_(1A) agonist cansuppressively control the neural circuit of anxiety/fear (Non-PatentLiterature 1). For example, buspirone and tandospirone which are5-HT_(1A) agonist are used as medicaments for treating generalizedanxiety disorder (GAD). In addition, 5-HT_(1A) agonist is expected toalso become a medicament for treating CNS diseases besides GAD such asmajor depression, obsessive-compulsive disorder, Parkinson's disease,Rett syndrome, and dementia.

The preferably-used treatment of GAD includes, particularly, theimprovement of psychiatric symptom and/or somatic symptom in GAD.

The preferably-used treatment of major depression includes,particularly, the improvement of psychiatric symptom and/or somaticsymptom in major depression.

The preferably-used treatment of obsessive-compulsive disorder includes,particularly, the improvement of compulsion and/or obsession inobsessive-compulsive disorder.

The preferably-used treatment of Parkinson's disease includes,particularly, the improvement of the symptom of L-DOPA-induceddyskinesia in Parkinson's disease.

The preferably-used treatment of Rett syndrome includes, particularly,the improvement of symptom of apnea in Rett syndrome.

Dementia includes, for example, Alzheimer-type dementia and Lewy bodydementia, and the preferably-used treatment of dementia includes,particularly, the treatment of peripheral symptom of the dementia (e.g.behavior disorder associated with Alzheimer-type dementia).

It is known that D₄ receptor controls the neural circuit involved inanxiety or fear formation. The stimulation of D₄ receptorhighly-expressed in medial prefrontal cortex is expected to be able tosuppressively control the activity of amygdala. Thus, D₄ agonist isexpected to exhibit antianxiety, like 5-HT_(1A) agonist.

Considering the above pharmacological knowledge, if both of 5-HT_(1A)receptor and D₄ receptor can be simultaneously stimulated to control theneural circuit system involved in anxiety from plural directions, suchmedicament stimulating the both receptors is expected to exhibit morepotent and broader antianxiety than existing 5-HT_(1A) agonists.

In addition, the present compound has an agonism for D₄ receptor,thereby the present compound is expected to become a medicament fortreating attention-deficit hyperactivity disorder (ADHD: which is ADHDdefined in Diagnostic and Statistical Manual of Mental Disorders, 5thedition (DSM-5), and was a disease name classified as attention-deficithyperactivity disorder in previous DSM-IV), and a CNS disease whichshows a similar symptom to ADHD, for example, autism spectrum disorder(autism spectrum disorder defined in Diagnostic and Statistical Manualof Mental Disorders, 5th edition (DSM-5), and was a disease nameclassified as autism, Asperger syndrome, atypical pervasivedevelopmental disorder, and childhood disintegrative disorder inprevious DSM-IV), schizophrenia which shows a similar symptom to ADHD,mood disorder, cognitive impairment, etc.

In the treatment of ADHD, in particular, it includes, preferably, ADHDwhose cardinal symptom is inattention, hyperactivity, and impulsivity.

In the treatment of autism spectrum disorder, in particular, itincludes, preferably, autism spectrum disorder whose cardinal symptom isa continuous defect of social communication and social interaction, anda pattern of limited repetitive behavior, interest, action, etc.

The present compound has an agonism for 5-HT_(1A) receptor and D₄receptor. For example, the present compound exhibits E_(max) value of50% or more, which indicates a maximum agonist activity for 5-HT_(1A)receptor and D₄ receptor, or EC₅₀ value of 100 nmol/L or less, whichindicates an agonist activity (Test 1).

In addition, the present compound has a potent binding affinity to5-HT_(1A) receptor and D₄ receptor (Test 2). In a preferred embodiment,the binding affinity of the present compound to 5-HT_(1A) receptor andD₄ receptor is 100 or more times potent compared with that of D₂receptor, thus the present compound can exert the pharmacological effectbased on 5-HT_(1A) and D₄ receptor agonism, without reaching the bloodlevel causing side effects such as extrapyramidal symptom andhyperprolactinemia which are thought to be caused by D₂ antagonisticaction.

In another preferred embodiment, the present compound is expected tohave a very small effect for cardiovascular system because there is abig difference between the inhibitory concentration of hERG channelwhich is an express indicator of arrhythmia in long QT, and the expressconcentration of the expected pharmacological effect (Test 5).

The disappearance half-life (T_(1/2)) of a medicament is a factor fordetermining the frequency of administration to retain the effect. It isthought that plural administrations of a medicament having a shortT_(1/2) per day can cause forgetting to take a medication or unfinishingtaking a medication, which can hinder a suitable medication.Furthermore, if the frequency of administration increases, it isconcerned that the incidence rate of side effects can increase or thetolerability can decrease in association with high-dose administration.From the viewpoint mentioned above, if a medicament having a longT_(1/2) is found out, the medicament is expected to be a long-actingmedicament with little concern mentioned above, which can bring inliability relief of medicated patients.

In a preferred embodiment of the present compound, the estimated humandisappearance half-life (T_(1/2)) of the present compound is 8 hours ormore (Test 4), it is expected that the drug efficacy can be retained fora long period in human body, the medication adherence of medicatedpatients can be improved, and a high tolerability can be exhibited atthe administration.

The present compound can be orally or parenterally administered. In caseof oral administration, the compound can be administered inconventionally-used dosage form. In case of parenteral administration,the compound can be administered in topical administration form,injection form, transdermal form, nasal form, etc. The oral form or therectal administration form include, for example, capsule, tablet, pill,powder, cachet, suppository, and liquid. The injection includes, forexample, aseptic solution and suspension. The topical administrationform includes, for example, cream, ointment, lotion, and transdermalformulation (e.g. normal patch and matrix).

The above-mentioned dosage forms can be prepared with a pharmaceuticallyacceptable excipient and additive in a conventional manner. Thepharmaceutically acceptable excipient and additive include carrier,binder, flavor, buffer, thickener, colorant, stabilizing agent,emulsifier, dispersant, suspending agent, and preservative.

The pharmaceutically acceptable carrier includes, for example, magnesiumcarbonate, magnesium stearate, talc, sugar, lactose, pectin, dextrin,starch, gelatin, tragacanth, methylcellulose, sodiumcarboxymethylcellulose, low-melting-point wax, and cocoa butter. Thecapsule form can be prepared by filling a capsule with the presentcompound and a pharmaceutically acceptable carrier. The present compoundcan be put into a capsule with or without a pharmaceutically acceptableexcipient. The cachet can be also prepared in a similar manner.

The injectable liquid form includes solution, suspension, and emulsion,for example, water solution, water-propylene glycol, etc. The liquidform may comprise water, and also it may be prepared in a solution ofpolyethylene glycol or/and propylene glycol. The liquid form suitablefor oral administration may be prepared by adding the present compoundto water and also adding colorant, flavor, stabilizing agent, sweetener,solubilizer, thickener, etc. thereto, as appropriate. Alternatively, theliquid form suitable for oral administration may be prepared by addingthe present compound with a dispersant to water and rendering the liquidsticky. The thickener used herein includes, for example,pharmaceutically acceptable natural or synthetic gum, resin,methylcellulose, sodium carboxymethylcellulose, and a known suspendingagent.

The dose of each compound can depend on patient's disease, age, bodyweight, gender, symptom, and the administration route, etc. In general,the present compound is administered to an adult (body weight: 50 kg) by0.1-1000 mg/day, preferably 0.1-300 mg/day, once a day or in 2-3 doses.Or, it may be administered once in a few days to a few weeks.

In order to enhance the effect and/or reduce the side effects thereof,the present compound and a pharmaceutically acceptable salt thereof maybe used in combination with another drug. For example, the presentcompound may be used in combination with an antianxiety drug such asselective serotonin reuptake inhibitor. Or, for example, the presentcompound may be used in combination with an antidepressant drug such asserotonin reuptake inhibitor.

The selective serotonin reuptake inhibitor includes, for example,sertraline, escitalopram, fluvoxamine, fluoxetine, paroxetine, andclomipramine. The serotonin reuptake inhibitor includes, for example,milnacipran, duloxetine, venlafaxine, amoxapine, clomipramine,nortriptyline, imipramine, and vortioxetine. Hereinafter, drugs withwhich the present compound may be used in combination are abbreviated as“concomitant drug”.

The administration interval of the present compound and its concomitantdrug is not limited, i.e., the concomitant drug may be administered atthe same time as the present compound or at a suitable interval. Or, thepresent compound and its concomitant drug can be formulated into acombination drug. The dose of the combination drug can be suitablydetermined based on the standard of the clinically-used dose thereof.The combination ratio of the present compound and its concomitant drugcan be suitably determined based on its subject patient, administrationroute, disease, pathology, concomitant drug, etc. For example, when thesubject patient is a human being, the concomitant drug may be used in0.01 to 100 part by weight per part of the present compound. For thepurpose of reducing the side effect, an antiemetic drug, asleep-inducing drug, an antiseizure drug, etc. may be used incombination as a concomitant drug.

EXAMPLES

The present invention is explained in more detail in the following byreferring to Reference examples, Examples, and Tests; however, thetechnical scope of the present invention is not limited thereto. Thecompound names used in Reference examples and Examples are not alwaysbased on IUPAC nomenclature system. In order to simplify description,abbreviations are sometimes used, the meanings of which are as definedabove. In the present description, the abbreviations shown below aresometimes used.

In the NMR data of Reference examples and Examples, the followingabbreviations are used.

Me: methyl

DMF: N,N-dimethylformamide

THF: tetrahydrofuran

tert-: tertiary

CDCl₃: deuterated chloroform

DMSO-d₆: deuterated dimethylsulfoxide

Proton nuclear magnetic resonance spectra were measured with FT-NMRspectrometer (300 MHz or 400 MHz, JEOL). The chemical shifts were shownin 6 value (ppm). The signs used in NMR denote the following meanings, δis singlet, d is doublet, dd is double doublet, dt is double triplet, tis triplet, q is quartet, m is multiplet, br is broad, brs is broadsinglet, and J is coupling constant.

Example 14,4-Difluoro-N-(2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)cyclohexane-carboxamide

To a mixture of the compound of Reference example 4 (600 mg),triethylamine (1.31 mL), 4,4-difluorocyclohexanecarboxylic acid (257mg), and DMF (5.0 mL) was addedO-(benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate(654 mg). The reaction mixture was stirred at room temperature for 8hours, and water was added thereto. The mixture was extracted with ethylacetate. The organic layer was dried over sodium sulfate, filtrated, andconcentrated in vacuo. The residue was purified by silica gel columnchromatography (chloroform/methanol) to give the title compound (406mg).

¹H-NMR (400 MHz, CDCl₃) δ: 1.48-2.06 (10H, m), 2.09-2.30 (5H, m), 2.54(2H, t, J=6.0 Hz), 2.77-2.88 (1H, m), 2.97-3.08 (2H, m), 3.38 (2H, dt,J=5.5, 5.5 Hz), 6.22 (1H, brs), 7.37 (1H, d, J=7.8 Hz), 7.52 (1H, d,J=7.8 Hz), 7.80 (1H, dd, J=7.8, 7.8 Hz).

Examples 2-7

According to the method of Example 1, Examples 2-7 were prepared fromthe corresponding Reference examples.

Example R¹— R²— Instrumental analyses data 2

—CF₃ ¹H-NMR (400 MHz, CDCl₃) δ: 1.55-1.67 (1H, m), 1.68-1.78 (1H, m),1.79-2.02 (6H, m), 2.10-2.20 (2H, m), 2.40-2.48 (1H, m), 2.52 (2H, t, J= 6.1 Hz), 2.77-2.86 (1H, m), 2.98-3.04 (2H, m), 3.29-3.46 (2H, m),3.57- 3.64 (1H, m), 3.70 (1H, dd, J = 11.6, 7.9 Hz), 3.79 (1H, dt, J =11.4, 4.6 Hz), 3.90 (1H, dd, J = 11.7, 3.7 Hz), 6.53 (1H, brs), 7.37(1H, d, J = 7.8 Hz), 7.51 (1H, d, J = 7.6 Hz), 7.79 (1H, dd, J = 7.8,7.8 Hz). 3

—Me ¹H-NMR (300 MHz, CDCl₃) δ: 1.55-1.67 (1H, m), 1.69-2.00 (9H, m),2.07-2.21 (2H, m), 2.46-2.58 (5H, m), 2.62-2.75 (1H, m), 2.83- 2.95 (1H,m), 2.95-3.05 (2H, m), 3.30-3.42 (2H, m), 4.59-4.71 (2H, m), 6.13 (1H,brs), 6.98 (2H, d, J = 7.9 Hz), 7.52 (1H, dd, J = 7.7, 7.7 Hz). 4

—Me ¹H-NMR (300 MHz, CDCl₃) δ: 1.67-2.02 (10H, m), 2.07-2.28 (5H, m),2.51 (2H, t, J = 5.9 Hz), 2.54 (3H, s), 2.63-2.75 (1H, m), 2.94- 3.05(2H, m), 3.33-3.40 (2H, m), 6.19 (1H, brs), 6.97 (1H, d, J = 7.7 Hz),6.99 (1H, d, J = 7.5 Hz), 7.52 (1H, dd, J = 7.7, 7.7 Hz). 5

—Me ¹H-NMR (400 MHz, CDCl₃) δ: 1.17 (6H, s), 1.72-1.85 (2H, m),1.92-2.00 (2H, m), 2.10- 2.21 (2H, m), 2.49-2.54 (5H, m), 2.64-2.74 (1H,m), 2.98-3.05 (2H, m), 3.31-3.39 (4H, m), 3.42 (3H, s), 6.96 (1H, d, J =7.8 Hz), 6.98 (1H, d, J = 7.6 Hz), 7.15 (1H, brs), 7.51 (1H, dd, J =7.7, 7.7 Hz). 6

—CF₃ ¹H-NMR (400 MHz, CDCl₃) δ: 1.17 (6H, s), 1.82-1.99 (4H, m ,2.10-2.20 (2H, m), 2.51 (2H, t, J = 6.2 Hz), 2.75-2.85 (1H, m),2.97-3.05 (2H, m), 3.32-3.40 (4H, m), 3.44 (3H, s), 7.35 (1H, d, J = 8.0Hz), 7.50 (1H, d, J = 7.8 Hz), 7.78 (1H, dd, J = 7.8, 7.8 Hz). 7

—CF₃ ¹H-NMR (400 MHz, CDCl₃) δ: 0.65 (2H, dd, J = 6.7, 4.0 Hz), 1.27(2H, dd, J = 6.7, 4.0 Hz), 1.89-1.96 (4H, m), 2.12-2.20 (2H, m), 2.54(2H, t, J = 6.2 Hz), 2.75-2.85 (1H, m), 3.00-3.07 (2H, m), 3.36-3.42(2H, m), 3.46 (2H, s), 3.49 (3H, s), 7.34 (1H, d, J = 7.8 Hz), 7.50 (1H,d, J = 7.8 Hz), 7.61 (1H, brs), 7.77 (1H, dd, J = 7.8, 7.8 Hz).

Example 8N-{2-[4-(6-Methylpyridin-2-yl)piperidin-1-yl]ethyl}-tetrahydro-2H-pyran-4-carboxamide

To a mixture of the compound of Reference example 6 (500 mg),triethylamine (1.27 mL), and dichloromethane (5.0 mL) was addedtetrahydro-2H-pyran-4-carbonylchloride (0.207 mL) under ice temperature.The reaction mixture was stirred at room temperature for 12 hours, andwater was added thereto. The mixture was extracted with chloroform. Theorganic layer was dried over sodium sulfate, filtrated, and concentratedin vacuo. The residue was purified by silica gel column chromatography(chloroform/methanol) to give the title compound (451 mg).

¹H-NMR (300 MHz, CDCl₃) δ: 1.71-1.90 (6H, m), 1.91-2.01 (2H, m),2.08-2.19 (2H, m), 2.31-2.43 (1H, m), 2.51 (2H, t, J=6.4 Hz), 2.54 (3H,s), 2.63-2.76 (1H, m), 2.95-3.04 (2H, m), 3.33-3.50 (4H, m), 3.99-4.07(2H, m), 6.20 (1H, brs), 6.98 (1H, d, J=7.7 Hz), 6.99 (1H, d, J=7.7 Hz),7.52 (1H, dd, J=7.7, 7.7 Hz).

Examples 9-10

According to the method of Example 8, Examples 9-10 were prepared fromthe corresponding Reference examples.

Example R¹— R²— Instrumental analyses data  9

—CF₃ ¹H-NMR (400 MHz, CDCl₃) δ: 1.21 (9H, s), 1.76- 1.89 (2H, m),1.95-2.04 (2H, m), 2.12-2.21 (2H, m), 2.53 (2H, t, J = 6.1 Hz),2.77-2.87 (1H, m), 2.98-3.05 (2H, m), 3.32-3.37 (2H, m), 6.35 (1H, brs),7.37 (1H, d, J = 7.8 Hz), 7.51 (1H, d, J = 7.6 Hz), 7.79 (1H, dd, J =7.9, 7.9 Hz). 10

—Me ¹H-NMR (300 MHz, CDCl₃) δ: 1.21 (9H, s), 1.68- 1.83 (2H, m),1.90-2.03 (2H, m), 2.10-2.21 (2H, m), 2.48-2.56 (5H, m), 2.63-2.76 (1H,m), 2.95-3.04 (2H, m), 3.30-3.37 (2H, m), 6.38 (1H, brs), 6.98 (2H, d, J= 7.7 Hz), 7.52 (1H, dd, J = 7.7, 7.7 Hz).

Example 11N-(2-{4-[6-(Trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)-tetrahydro-2H-pyran-4-carboxamide

To a mixture of the compound of Reference example 4 (350 mg),triethylamine (0.765 mL), and dichloromethane (3.0 mL) was addedtetrahydro-2H-pyran-4-carbonylchloride (0.124 mL) under ice temperature.The reaction mixture was stirred at room temperature for 12 hours, andwater was added thereto. The mixture was extracted with chloroform. Theorganic layer was dried over sodium sulfate, filtrated, and concentratedin vacuo. The residue was purified by silica gel column chromatography(chloroform/methanol) to give the title compound (232 mg).

¹H-NMR (300 MHz, CDCl₃) δ: 1.71-2.02 (8H, m), 2.08-2.21 (2H, m),2.32-2.44 (1H, m), 2.52 (2H, t, J=6.0 Hz), 2.75-2.88 (1H, m), 2.95-3.05(2H, m), 3.33-3.50 (4H, m), 3.99-4.08 (2H, m), 6.15 (1H, brs), 7.37 (1H,d, J=8.1 Hz), 7.52 (1H, d, J=7.7 Hz), 7.79 (1H, dd, J=7.9, 7.9 Hz).

Example 124,4-Difluoro-N-{2-[6-(trifluoromethyl)-3′,6′-dihydro[2,4′-bipyridin]-1′(2′H)-yl]ethyl}-cyclohexane-1-carboxamide

A mixture of 4,4-difluorocyclohexane-1-carboxylic acid (42.0 mg),triethylamine (0.178 mL),1-[bis(dimethylamino)methylene]-1H-benzotriazolium-3-oxidehexafluorophosphate (89.0 mg), and N,N-dimethylformamide (1.0 mL) wasstirred at room temperature for 20 minutes, and the compound ofReference example 7 (81.2 mg) was added thereto. The reaction mixturewas stirred at room temperature for 24 hours, and water (30 mL) wasadded thereto. The mixture was extracted with ethyl acetate (30 mL×2),washed with 1 mol/L aqueous sodium hydroxide (10 mL), dried overanhydrous magnesium sulfate, filtrated, and then concentrated. Theresidue was purified by preparative thin-layer column chromatography(dichloromethane/methanol) to give the title compound (40 mg).

¹H-NMR (300 MHz, DMSO-d₆) δ: 1.50-1.90 (6H, m), 2.01 (2H, t, J=11.3 Hz),2.18-2.34 (2H, m), 2.50-2.58 (3H, m), 2.66 (2H, t, J=5.6 Hz), 3.15-3.27(4H, m), 6.81 (1H, s), 7.73 (1H, d, J=7.6 Hz), 7.79 (1H, t, J=5.6 Hz),7.85 (1H, d, J=8.1 Hz), 8.04 (1H, dd, J=7.9, 7.9 Hz).

Examples 13-15

According to the method of Example 12, Examples 13-15 were prepared fromthe corresponding Reference examples.

Example Chemical structure Instrumental analyses data 13

¹H-NMR (300 MHz, CDCl₃) δ: 1.40-1.57 (2H, m), 1.71-1.80 (2H, m),1.85-1.93 (2H, m), 2.49-2.59 (4H, m), 2.59-2.72 (4H, m), 2.77 (2H, dd, J= 5.9, 4.5 Hz), 3.26 (2H, q, J = 2.9 Hz), 3.42 (2H, td, J = 6.2, 5.2Hz), 4.58-4.75 (2H, m), 6.51 (1H, s), 6.62-6.71 (1H, m), 7.02 (1H, d, J= 7.6 Hz), 7.16 (1H, d, J = 7.8 Hz), 7.54 (1H, dd, J = 7.7, 7.7 Hz). 14

¹H-NMR (300 MHz, CDCl₃) δ: 1.62-2.02 (6H, m), 2.08-2.27 (3H, m), 2.57(3H, s), 2.61- 2.75 (4H, m), 2.80 (2H, t, J = 5.6 Hz), 3.27 (2H, d, J =3.3 Hz), 3.45 (2H, q, J = 5.4 Hz), 6.31 (1H, s), 6.62-6.73 (1H, m), 7.04(1H, d, J = 7.6 Hz), 7.17 (1H, d, J = 7.9 Hz), 7.56 (1H, dd, J = 7.7,7.7 Hz). 15

¹H-NMR (300 MHz, CDCl₃) δ: 1.55-1.70 (1H, m), 1.70-1.90 (3H, m),1.89-2.03 (4H, m), 2.08-2.25 2H, m), 2.39-2.50 (1H, m), 2.50-2.59 (5H,m), 2.72 (1H, tt, J = 11.9, 3.8 Hz), 2.93-3.10 (2H, m), 3.26- 3.49 (2H,m), 3.59 (1H, ddd, J = 11.7, 8.9, 3.3 Hz), 3.70 (1H, dd, J = 11.5, 8.1Hz), 3.82 (1H, td, J = 11.4, 4.4 Hz), 3.94 1H, dd, J = 11.5, 3.9 Hz),6.56 (1H, s), 7.00 (2H, d, J = 7.7 Hz), 7.53 (1H, dd, J = 7.7, 7.7 Hz).

Example 16N-{2-[6-(Trifluoromethyl)-3′,6′-dihydro[2,4′-bipyridin]-1′(2′H)-yl]ethyl}-tetrahydro-2H-pyran-3-carboxamide

To a mixture of oxane-3-carboxylic acid (41.0 mg), triethylamine (0.263mL), and acetonitrile (2.0 mL) was added 50% propylphosphonic acidanhydride/acetonitrile solution (301 mg) dropwise, and the mixture wasstirred at room temperature for 10 minutes. The compound of Referenceexample 7 (144 mg) was added thereto, and the reaction mixture wasstirred at room temperature for 24 hours. The solvent was removed fromthe reaction mixture, and water (30 mL) was added to the residue. Themixture was extracted with ethyl acetate (30 mL×2), washed with aqueoussaturated sodium bicarbonate (30 mL), dried over anhydrous sodiumsulfate, filtrated, and then concentrated. The residue was purified bypreparative thin-layer column chromatography (dichloromethane/methanol)to give the title compound (22.0 mg).

¹H-NMR (300 MHz, CDCl₃) δ: 1.44-1.78 (4H, m), 1.81-2.00 (2H, m),2.37-2.49 (1H, m), 2.63-2.83 (4H, m), 3.28 (2H, q, J=2.9 Hz), 3.39-3.50(2H, m), 3.55 (1H, ddd, J=11.3, 9.1, 3.3 Hz), 3.68 (1H, dd, J=11.5, 8.2Hz), 3.80 (1H, td, J=11.4, 4.4 Hz), 3.92 (1H, dd, J=11.7, 3.8 Hz), 6.47(1H, s), 6.80 (1H, tt, J=3.6, 1.5 Hz), 7.45-7.62 (2H, m), 7.76-7.89 (1H,m).

Examples 17-28

According to the method of Example 16, Examples 17-28 were prepared fromthe corresponding Reference examples.

Example Chemical structure Instrumental analyses data 17

¹H-NMR (300 MHz, CDCl₃) δ: 1.17 (6H, s), 2.56 (3H, s), 2.59-2.71 (4H,m), 2.72-2.81 (2H, m), 3.26 (2H, q, J = 2.9 Hz), 3.33 (2H, s), 3.35 (3H,s), 3.42 (2H, td, J = 6.2, 4.9 Hz), 6.69 (1H, tt, J = 3.6, 1.6 Hz), 7.02(1H, d, J = 7.6 Hz), 7.16 (2H, d, J = 7.8 Hz), 7.54 (1H, dd, J = 7.7,7.7 Hz). 18

¹H-NMR (300 MHz, CDCl₃) δ: 1.19 (6H, s), 2.86-2.94 (2H, m), 3.01 (2H, t,J = 6.1 Hz), 3.16 (2H, t, J = 5.9 Hz), 3.36 (2H, s), 3.37 (3H, s),3.50-3.72 (4H, m), 6.68-6.78 (1H, m), 7.47 (1H, s), 7.59 (2H, dd, J =7.9, 5.5 Hz), 7.86 (1H, dd, J = 7.9, 7.9 Hz), 8.34 (1H, s). 19

¹H-NMR (300 MHz, CDCl₃) δ: 1.71-1.92 (4H, m), 2.27-2.43 (1H, m),2.61-2.82 (6H, m), 3.27 (2H, q, J = 2.9 Hz), 3.33-3.52 (4H, m),3.93-4.09 (2H, m), 6.15 (1H, s), 6.80 (1H, td, J = 3.5, 1.7 Hz), 7.56(2H, dd, J = 10.7, 7.9 Hz), 7.84 (1H, dd, J = 7.9, 7.9 Hz). 20

¹H-NMR (300 MHz, CDCl₃) δ: 1.33-1.49 (1H, m), 1.51-1.67 (3H, m),1.78-2.02 (5H, m), 2.08-2.22 (3H, m), 2.48-2.60 (5H, m), 2.71 (1H, tt, J= 12.0, 3.9 Hz), 3.05 (2H, td, J = 11.5, 3.2 Hz), 3.33-3.46 (2H, m),3.51 (1H, td, J = 11.2, 3.4 Hz), 3.80 (1H, dd, J = 11.2, 2.5 Hz),4.03-4.13 (1H, m), 6.94 (1H, s), 7.00 (2H, dd, J = 7.6, 1.9 Hz), 7.53(1H, dd, J = 7.7, 7.7 Hz). 21

¹H-NMR (300 MHz, CDCl₃) δ: 1.41-1.58 (2H, m), 1.71-1.83 (2H, m),1.83-1.95 (4H, m), 1.99 (2H, d, J = 13.2 Hz), 2.09-2.27 (2H, m),2.43-2.65 (3H, m), 2.83 (1H, tt, J = 11.7, 4.0 Hz), 2.94-3.11 (2H, m),3.37 (2H, q, J = 6.0 Hz), 4.62-4.78 (2H, m), 6.58 (1H, s), 7.39 (1H, d,J = 7.9 Hz), 7.53 (1H, dd, J = 7.7, 0.9 Hz), 7.81 (1H, dd, J = 7.8, 7.8Hz). 22

¹H-NMR (300 MHz, CDCl₃) δ: 1.83 (2H, qd, J = 12.4, 3.8 Hz), 1.93-2.02(2H, m), 2.08-2.25 (4H, m), 2.47-2.60 (5H, m), 2.71 (1H, tt, J = 11.9,3.9 Hz), 2.88-2.98 (1H, m), 3.00-3.07 (2H, m), 3.40 (2H, q, J = 5.6 Hz),3.79-4.04 (4H, m), 6.39 (1H, s), 6.99 (2H, dd, J = 7.8, 2.4 Hz), 7.53(1H, dd, J = 7.7, 7.7 Hz). 23

¹H-NMR (300 MHz, CDCl₃) δ: 1.83-2.07 (4H, m), 2.14-2.30 (4H, m),2.56-2.63 (2H, m), 2.79-2.90 (1H, m), 2.91-3.03 (1H, m), 3.03-3.10 (2H,m), 3.42 (2H, q, J = 5.6 Hz), 3.80-4.07 (4H, m), 6.32 (1H, s), 7.40 (1H,d, J = 7.9 Hz), 7.54 (1H, dd, J = 7.7, 0.9 Hz), 7.82 (1H, dd, J = 7.8,7.8 Hz). 24

¹H-NMR (300 MHz, CDCl₃) δ: 1.74-1.91 (3H, m), 1.91-2.04 (3H, m),2.04-2.23 (3H, m), 2.30 (1H, dd, J = 12.7, 7.7 Hz), 2.46-2.62 (5H, m),2.71 (1H, tt, J = 12.1, 3.7 Hz), 2.95-3.08 (2H, m), 3.41 (2H, q, J = 6.0Hz), 3.87-4.04 (2H, m), 4.39 (1H, dd, J = 8.4, 5.5 Hz), 7.00 (2H, d, J =7.7 Hz), 7.12 (1H, s), 7.53 (1H, dd, J = 7.7, 7.7 Hz). 25

¹H-NMR (300 MHz, CDCl₃) δ: 1.79-2.03 (6H, m), 2.06-2.38 (4H, m), 2.57(2H, dd, J = 6.3, 1.6 Hz), 2.84 (1H, tt J = 11.8, 4.1 Hz), 2.96-3.10(2H, m), 3.41 (2H, q, J = 6.0 Hz), 3.83-4.06 (2H, m), 4.39 (1H, dd, J =8.4, 5.5 Hz), 7.12 (1H, s), 7.39 (1H, d, J = 7.9 Hz), 7.53 (1H, dd, J =7.8, 0.9 Hz), 7.81 (1H, dd, J = 7.8, 7.8 Hz). 26

¹H-NMR (300 MHz, DMSO-d₆) δ: 1.00-1.15 (2H, m), 1.30-1.47 (2H, m),1.63-1.83 (5H, m), 1.96-2.10 (5H, m), 2.35 (2H, t, J = 6.9 Hz), 2.43(3H, s), 2.55-2.62 (2H, m), 2.94 (2H, d, J = 11.2 Hz), 3.01- 3.10 (1H,m), 3.16 (2H, q, J = 6.5 Hz), 3.23 (3H, s), 7.04 (2H, dd, J = 7.6, 2.5Hz), 7.58 (1H, dd, J = 7.7, 7.7 Hz), 7.64 (1H, d, J = 5.6 Hz). 27

¹H-NMR (300 MHz, DMSO-d₆) δ: 1.09 (2H, t, J = 12.3 Hz), 1.37 (2H, d, J =13.0 Hz), 1.68-1.86 (5H, m), 1.95-2.11 (5H, m), 2.30-2.39 (2H, m),2.70-2.80 (1H, m), 2.92-3.01 (2H, m), 3.06 (1H, s), 3.13- 3.19 (1H, m),3.23 (3H, s), 7.58-7.69 (2H, m), 7.72 (1H, d, J = 7.7 Hz), 8.02 (1H, dd,J = 7.8, 7.8 Hz). 28

¹H-NMR (300 MHz, DMSO-d₆) δ: 1.49-1.63 (4H, m), 1.78 (4H, s), 2.04 (2H,s), 2.36 (3H, d, J = 2.9 Hz), 2.57-2.72 (1H, m), 2.94 (2H, d, J = 11.0Hz), 3.11-3.31 (4H, m), 3.85 (2H, td, J = 11.2, 3.4 Hz), 7.09 (1H, d, J= 8.0 Hz), 7.32 (1H, d, J = 7.6 Hz), 7.71 (1H, s), 7.93 (1H, dd, J =7.8, 7.8 Hz).

Example 29N-[2-(6-Methyl-3′,6′-dihydro[2,4′-bipyridin]-1′(2′H)-yl)ethyl]-tetrahydro-2H-pyran-4-carboxamide

To a mixture of the compound of Reference example 8 (150 mg), sodiumbicarbonate (231 mg), and dichloromethane (5.0 mL) was slowly addedtetrahydro-2H-pyran-4-carbonylchloride (81.8 mg) under ice temperature.The mixture was stirred at room temperature for 20 hours, and 10%aqueous potassium carbonate (30 mL) was added thereto. The mixture wasstirred at room temperature for 15 minutes. The organic layer wasseparated, washed with brine, dried over anhydrous magnesium sulfate,filtrated, and then concentrated. The residue was purified bypreparative thin-layer column chromatography (chloroform/3 mol/Lammonia/methanol) to give the title compound (99.0 mg).

¹H-NMR (300 MHz, CDCl₃) δ: 1.71-1.90 (4H, m), 2.30-2.43 (1H, m), 2.57(3H, s), 2.64-2.75 (4H, m), 2.75-2.83 (2H, m), 3.23-3.31 (2H, m),3.37-3.52 (4H, m), 3.98-4.08 (2H, m), 6.27 (1H, s), 6.63-6.71 (1H, m),7.04 (1H, d, J=7.6 Hz), 7.17 (1H, d, J=7.8 Hz), 7.56 (1H, dd, J=7.7, 7.7Hz).

Example 302,2-Dimethyl-N-[2-(6-methyl-3′,6′-dihydro[2,4′-bipyridin]-1′(2′H)-yl)ethyl]propanamide

According to the method of Example 29, the title compound (48 mg) wasprepared from Reference example 8 (150 mg).

¹H-NMR (300 MHz, DMSO-d₆) δ: 1.08 (9H, s), 2.45 (3H, s), 2.47-2.54 (4H,m), 2.65 (2H, t, J=5.6 Hz), 3.13-3.18 (2H, m), 3.19-3.26 (2H, m),6.58-6.72 (1H, m), 7.09 (1H, d, J=7.6 Hz), 7.29 (1H, d, J=7.9 Hz), 7.38(1H, dd, J=5.6, 5.6 Hz), 7.63 (1H, dd, J=7.7, 7.7 Hz).

Example 312,2-Dimethyl-N-{2-[6-(trifluoromethyl)-3′,6′-dihydro[2,4′-bipyridin]-1′(2′H)-yl]ethyl}propanamide

To a mixture of the compound of Reference example 7 (160 mg),triethylamine (0.319 mL), and dichloromethane (2.0 mL) was slowly addedpivaloyl chloride (46.0 mg). The reaction mixture was stirred at roomtemperature for 20 hours, and then water (30 mL) was added thereto. Themixture was extracted with ethyl acetate (30 mL×2), washed with brine(30 mL), dried over anhydrous sodium sulfate, filtrated, and thenconcentrated. The residue was purified by preparative HPLC to give thetitle compound (23 mg) as its formate.

¹H-NMR (300 MHz, CDCl₃) δ: 1.23 (9H, s), 2.84-2.97 (2H, m), 3.05-3.13(2H, m), 3.18 (2H, t, J=5.7 Hz), 3.58-3.64 (2H, m), 3.66-3.70 (2H, m),6.75 (1H, s), 6.92 (1H, s), 7.61 (2H, dd, J=10.5, 7.8 Hz), 7.88 (1H, dd,J=7.9, 7.9 Hz).

Examples 32-34

According to the method of Example 31, Examples 32-34 were prepared fromthe corresponding Reference examples.

Example Chemical structure Instrumental analyses data 32

¹H-NMR (300 MHz, CDCl₃) δ: 1.74-1.99 (8H, m), 2.14 (2H, td, J = 11.6,2.8 Hz), 2.39 (1H, tt, J = 10.5, 4.9 Hz), 2.53 (2H, t, J = 5.9 Hz), 2.69(1H, tt, J = 11.5, 4.2 Hz), 3.01 (2H, td, J = 11.9, 3.2 Hz), 3.34-3.53(4H, m), 3.98- 4.11 (2H, m), 6.20 (1H, s), 6.79 (1H, dd, J = 8.1, 2.9Hz), 7.07 (1H, dd, J = 7.4, 2.5 Hz), 7.74 (1H, dd, J = 8.0, 8.0 Hz). 33

¹H-NMR (300 MHz, DMSO-d₆) δ: 1.53-1.62 (4H, m), 1.67-1.87 (4H, m), 2.05(2H, s), 2.30- 2.41 (3H, m), 2.54-2.60 (1H) m), 2.94-3.00 (2H, m) 3.16-3.23 (2H, m), 3.29 (2H, tt, J = 7.9, 3.8 Hz), 3.80-3.89 (5H, m), 6.61(1H, dd, J = 8.2, 0.7 Hz), 6.83 (1H, d, J = 7.2 Hz), 7.60 (1H, dd, J =8.2, 7.3 Hz), 7.71 (1H, s). 34

¹H-NMR (300 MHz, CDCl₃) δ: 1.73-2.10 (8H, m), 2.11-2.29 (2H, m),2.34-2.46 (1H, m), 2.52-2.66 (2H, m), 2.73-2.87 (1H, m), 3.00-3.10 (2H,m), 3.34-3.59 (4H, m), 4.01-4.11 (2H, m), 6.62 (1H, t, J = 55.6 Hz),7.33 (1H, s), 7.50 (1H, d, J = 7.7 Hz), 7.80 (1H, dd, J = 7.8, 7.8 Hz).

Example 35N-{2-[4-(6-Cyanopyridin-2-yl)piperidin-1-yl]ethyl}-tetrahydro-2H-pyran-4-carboxamide

A mixture of the compound of Example 32 (180 mg), sodium cyanide (500mg), and dimethylsulfoxide (10 mL) was stirred at 150° C. for 72 hours,and then water (100 mL) was added thereto. The mixture was extractedwith ethyl acetate (100 mL×2), washed with aqueous saturated sodiumbicarbonate, dried over anhydrous magnesium sulfate, filtrated, and thenconcentrated. The residue was purified by preparative thin-layer columnchromatography (dichloromethane/3 mol/L ammonia/methanol) to give thetitle compound (11.0 mg). ¹H-NMR (300 MHz, DMSO-d₆) δ: 1.52-1.60 (4H,m), 1.62-1.87 (4H, m), 1.94-2.17 (2H, m), 2.25-2.43 (3H, m), 2.66-2.80(1H, m), 2.96 (2H, d, J=10.9 Hz), 3.09-3.31 (4H, m), 3.85 (2H, td,J=11.2, 3.4 Hz), 7.67 (2H, dd, J=8.0, 1.1 Hz), 7.87 (1H, dd, J=7.7, 1.1Hz), 7.98 (1H, dd, J=7.8, 7.8 Hz).

Example 36N-{2-[4-(6-Aminopyridin-2-yl)piperidin-1-yl]ethyl}-tetrahydro-2H-pyran-4-carboxamide

A mixture of the compound of Reference example 15 (270 mg), 50% Raneynickel/water-suspension (0.2 mL), and methanol (5.0 mL) was stirredunder hydrogen atmosphere at room temperature for 24 hours. The reactionmixture was filtrated on Celite, and washed with methanol (10 mL×2). Thefiltrate was concentrated. The residue was triturated with a mixture ofdichloromethane and diethyl ether to give the title compound (22 mg).

¹H-NMR (300 MHz, DMSO-d₆) δ: 1.49-1.61 (4H, m), 1.62-1.77 (4H, m), 1.99(2H, td, J=11.3, 3.0 Hz), 2.25-2.42 (4H, m), 2.87-2.98 (2H, m), 3.17(2H, q, J=6.5 Hz), 3.23-3.32 (2H, m), 3.85 (2H, td, J=11.2, 3.4 Hz),5.72 (2H, s), 6.25 (1H, d, J=8.1 Hz), 6.34 (1H, d, J=7.3 Hz), 7.27 (1H,dd, J=7.7, 7.7 Hz), 7.68 (1H, J=5.6, 5.6 Hz).

Example 37N-(2-{4-[6-(Methylamino)pyridin-2-yl]piperidin-1-yl}ethyl)-tetrahydro-2H-pyran-4-carboxamide

To a solution of the compound of Example 36 (100 mg) in methanol (1.0mL) were added paraformaldehyde (36.0 mg) and sodium methoxide (81.0mg). The reaction mixture was refluxed for 2 hours. The reaction mixturewas cooled under ice temperature, sodium borohydride (46.0 mg) was addedto the cooled reaction mixture, and then the mixture was refluxed for 2hours. To the reaction mixture was added aqueous saturated sodiumbicarbonate (5.0 mL). The mixture was extracted with ethyl acetate (30mL×2), dried over anhydrous magnesium sulfate, filtrated, and thenconcentrated. The residue was purified by preparative thin-layer columnchromatography (dichloromethane/3 mol/L ammonia/methanol) to give thetitle compound (36.0 mg).

¹H-NMR (300 MHz, CDCl₃) δ: 1.68-1.89 (6H, m), 1.89-2.01 (2H, m),2.04-2.22 (2H, m), 2.39 (1H, tt, J=10.4, 5.3 Hz), 2.46-2.60 (3H, m),2.92 (3H, d, J-5.1 Hz), 2.95-3.07 (2H, m), 3.29-3.54 (4H, m), 4.05 (2H,td, J=11.5, 3.6 Hz), 4.36-4.62 (1H, m), 6.25 (2H, d, J=8.2 Hz), 6.49(1H, d, J=7.3 Hz), 7.43 (1H, dd, J=8.2, 7.4 Hz).

Example 38N-(2-{4-[6-(Dimethylamino)pyridin-2-yl]piperidin-1-yl}ethyl)-tetrahydro-2H-pyran-4-carboxamide

To a solution of the compound of Reference example 36 (50.0 mg) indichloroethane (1.5 mL) was added paraformaldehyde (18.0 mg), and thereaction mixture was stirred at room temperature for 1 hour. Sodiumcyanoborohydride (23.9 mg) was added thereto, and the reaction mixturewas stirred at room temperature for 24 hours. To the reaction mixturewas added dichloromethane (30 mL). The mixture was washed with aqueoussaturated sodium bicarbonate (10 mL×2), dried over anhydrous sodiumsulfate, filtrated, and then concentrated. The residue was purified bypreparative thin-layer column chromatography (dichloromethane/3 mol/Lammonia/methanol) to give the title compound (36.0 mg).

¹H-NMR (300 MHz, CDCl₃) δ: 1.75-2.02 (8H, m), 2.15 (2H, t, J=11.5 Hz),2.32-2.46 (1H, m), 2.48-2.64 (3H, m), 3.00 (2H, d, J=11.3 Hz), 3.10 (6H,s), 3.33-3.53 (4H, m), 4.04 (2H, td, J=11.4, 3.4 Hz), 6.28 (1H, s), 6.37(1H, d, J=8.6 Hz), 6.44 (1H, d, J=7.3 Hz), 7.40 (1H, dd, J=8.4, 7.3 Hz).

Reference Example 16-(Trifluoromethyl)-1′,2′,3′,6′-tetrahydro-2,4′-bipyridine

To a mixture ofN-Boc-1,2,3,6-tetrahydro-4-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)-pyridine(41.0 g), dimethoxyethane (221 mL), and water (111 mL) were added2-bromo-6-(trifluoromethyl)pyridine (30.0 g), sodium carbonate (70.3 g),and tetrakis(triphenylphosphine)palladium(0) (7.67 g). The reactionmixture was stirred at 80° C. for 15 hours, and then concentratedhydrochloric acid (300 mL) was slowly added dropwise thereto. Thereaction mixture was stirred at room temperature for 1 hour, and thenfiltrated on Celite. The filtrate was washed with chloroform. To theaqueous layer was added 20% aqueous sodium hydroxide (375 mL), andextracted with chloroform. The organic layer was dried over sodiumsulfate, filtrated, and then concentrated in vacuo to give the titlecompound (26.9 g).

¹H-NMR (400 MHz, CDCl₃) δ: 2.53-2.59 (2H, m), 3.11 (2H, t, J=5.7 Hz),3.59 (2H, q, J=3.0 Hz), 6.81-6.84 (1H, m), 7.48 (1H, d, J=7.8 Hz), 7.51(1H, d, J=8.0 Hz), 7.78 (1H, dd, J=7.9, 7.9 Hz).

Reference Example 2 2-(Piperidin-4-yl)-6-(trifluoromethyl)pyridine

To a solution of the compound of Reference example 1 (53.8 g) inmethanol (236 mL) was added 10% palladium/carbon (12.5 g), and thereaction mixture was stirred under hydrogen atmosphere at roomtemperature for 15 hours. The reaction mixture was filtrated on Celite,and the filtrate was concentrated in vacuo to give the title compound(54.1 g).

¹H-NMR (400 MHz, CDCl₃) δ: 1.73-1.85 (2H, m), 1.95-2.02 (2H, m),2.76-2.85 (2H, m), 2.90-2.99 (1H, m), 3.23-3.30 (2H, m), 7.36 (1H, d,J=7.8 Hz), 7.49 (1H, d, J=7.8 Hz), 7.78 (1H, dd, J=7.8, 7.8 Hz).

Reference Example 3 tert-Butyl (2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)carbamate

To a mixture of the compound of Reference example 2 (9.62 g),tetrabutylammonium bromide (1.35 g), 50% aqueous potassium carbonate(57.7 g), and THF (84 mL) was added tert-butyl (2-bromoethyl)carbamate(9.83 g). The reaction mixture was stirred at 70° C. for 15 hours, waterwas added thereto, and the mixture was extracted with ethyl acetate. Theorganic layer was dried over sodium sulfate, filtrated, and concentratedin vacuo. The residue was purified by silica gel column chromatography(chloroform/methanol) to give the title compound (11.0 g).

¹H-NMR (400 MHz, CDCl₃) δ: 1.44 (9H, s), 1.76-1.97 (4H, m), 2.05-2.14(2H, m), 2.47 (2H, t, J=6.0 Hz), 2.73-2.84 (1H, m), 2.95-3.03 (2H, m),3.17-3.28 (2H, m), 5.01 (1H, brs), 7.35 (1H, d, J=7.8 Hz), 7.49 (1H, d,J=7.8 Hz), 7.77 (1H, dd, J=7.8, 7.8 Hz).

Reference Example 42-{4-[6-(Trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethylaminetrihydrochloride

To a solution of the compound of Reference example 3 (1.57 g) indichloromethane (8.4 mL) was added 4 mol/L hydrochloric acid/ethylacetate (10.5 mL). The reaction mixture was stirred at room temperaturefor 4 hours, and the solvent was removed. The residue was stirred indiethyl ether and filtrated to give the title compound (1.37 g).

¹H-NMR (400 MHz, DMSO-D₆) δ: 2.06-2.17 (4H, m), 3.07-3.22 (3H, m),3.27-3.45 (4H, m), 3.63-3.71 (2H, m), 7.65 (1H, d, J=7.8 Hz), 7.78 (1H,d, J=7.8 Hz), 8.08 (1H, dd, J=7.8, 7.8 Hz), 8.43 (3H, brs).

Reference Example 5 6-Methyl-1′,2′,3′,6′-tetrahydro-2,4′-bipyridine

To a mixture of 2-bromo-6-methylpyridine (5.11 g), dimethoxyethane (79mL), and water (20 mL) were addedN-Boc-1,2,3,6-tetrahydro-4-(4,4,5,5-tetramethyl-[1,3,2]-dioxaborolan-2-yl)-pyridine(11.0 g), potassium carbonate (8.21 g), andtetrakis(triphenylphosphine)palladium(0) (3.43 g). The reaction mixturewas stirred at 80° C. for 4 hours, water was added thereto, and themixture was extracted with ethyl acetate. The organic layer was driedover sodium sulfate, filtrated, and concentrated in vacuo. The residuewas purified by silica gel column chromatography (hexane/ethyl acetate).

To a solution of the purified product in ethyl acetate (20 mL) was added4 mol/L hydrochloric acid/ethyl acetate (20 mL). The reaction mixturewas stirred at room temperature for 24 hours, and then concentrated. Tothe residue was added aqueous saturated sodium bicarbonate, and themixture was extracted with chloroform/methanol solution. The organiclayer was dried over sodium sulfate, filtrated, and concentrated invacuo. The residue was purified by amino silica gel columnchromatography (chloroform/methanol) to give the title compound (4.88g).

¹H-NMR (400 MHz, CDCl₃) δ: 2.51-2.57 (5H, m), 3.12 (2H, t, J=5.7 Hz),3.58 (2H, q, J=3.1 Hz), 6.70-6.74 (1H, m), 7.00 (1H, d, J=7.8 Hz), 7.13(1H, d, J=7.8 Hz), 7.53 (1H, dd, J=7.8, 7.8 Hz).

Reference Example 6 2-[4-(6-Methylpyridin-2-yl)piperidin-1-yl]ethylaminetrihydrochloride

According to the method of Reference examples 2-4, the title compoundwas prepared from Reference example 5.

¹H-NMR (300 MHz, DMSO-D₆) δ: 2.11-2.35 (4H, m), 2.78 (3H, s), 3.13-3.29(2H, m), 3.31-3.46 (4H, m), 3.47-3.61 (1H, m), 3.66-3.78 (2H, m), 7.65(1H, d, J=8.1 Hz), 7.77 (1H, d, J=7.5 Hz), 8.41 (1H, dd, J=7.8, 7.8 Hz),8.47 (3H, brs), 11.30 (1H, brs).

Reference Example 72-[6-(Trifluoromethyl)-3′,6′-dihydro[2,4′-bipyridin]-1′(2′H)-yl]ethylaminetrihydrochloride

According to the method of Reference examples 3-4, the title compoundwas prepared from Reference example 1.

¹H-NMR (300 MHz, D₂O) δ: 2.84-3.02 (2H, m), 3.44-3.55 (2H, m), 3.56-3.69(4H, m), 3.99-4.10 (2H, m), 6.50-6.59 (1H, m), 7.72 (1H, d, J=3.7 Hz),7.75 (1H, d, J=3.3 Hz), 8.00 (1H, dd, J=7.9, 7.9 Hz).

Reference Example 82-(6-Methyl-3′,6′-dihydro[2,4′-bipyridin]-1′(2′H)-yl)ethylaminetrihydrochloride

According to the method of Reference examples 3-4, the title compoundwas prepared from Reference example 5.

¹H-NMR (300 MHz, DMSO-d₆) δ: 2.68 (3H, s), 2.95-3.07 (2H, m), 3.33-3.45(3H, m), 3.48-3.56 (2H, m), 3.70-3.84 (1H, m), 3.94-4.07 (1H, m),4.12-4.27 (1H, m), 6.83 (1H, d, J=3.9 Hz), 7.55 (1H, d, J=7.8 Hz), 7.69(1H, d, J=8.0 Hz), 8.12 (1H, dd, J=8.2, 8.2 Hz), 8.60 (3H, s), 11.64(1H, s).

Reference Example 9 tert-Butyl{2-[6-(trifluoromethoxy)-3′,6′-dihydro[2,4′-bipyridin]-1′(2′H)-yl]ethyl}carbamate

According to the method of Reference examples 1 and 3, the titlecompound was prepared from 2-chloro-6-trifluoromethoxypyridine.

¹H-NMR (300 MHz, CDCl₃) δ: 1.47 (9H, s), 2.58-2.70 (4H, m), 2.71-2.79(2H, m), 3.20-3.28 (2H, m), 3.28-3.36 (2H, m), 6.73-6.82 (1H, m), 6.85(1H, d, J=8.0 Hz), 7.23-7.30 (1H, m), 7.74 (1H, dd, J=7.9, 7.9 Hz).

Reference Example 10 tert-Butyl (2-{4-[6-(trifluoromethoxy)pyridin-2-yl]piperidin-1-yl}ethyl)carbamate

According to the method of Reference example 2, the title compound wasprepared from Reference example 9.

¹H-NMR (300 MHz, CDCl₃) δ: 1.47 (9H, s), 1.82-2.07 (4H, m), 2.18-2.30(2H, m), 2.49-2.62 (2H, m), 2.66-2.79 (1H, m), 3.10 (2H, d, J=11.2 Hz),3.24-3.40 (2H, m), 6.87 (1H, d, J=8.1 Hz), 7.11 (1H, d, J=7.5 Hz), 7.73(1H, dd, J=7.8, 7.8 Hz).

Reference Example 112-{4-[6-(Trifluoromethoxy)pyridin-2-yl]piperidin-1-yl}ethylaminetrihydrochloride

According to the method of Reference example 4, the title compound wasprepared from Reference example 10.

¹H-NMR (300 MHz, D₂O) δ: 1.93-2.14 (2H, m), 2.15-2.26 (2H, m), 3.04-3.13(1H, m), 3.16-3.33 (2H, m), 3.38-3.54 (4H, m), 3.62-3.77 (2H, m), 7.13(1H, d, J=8.2 Hz), 7.31 (1H, d, J=7.6 Hz), 7.91 (1H, dd, J=7.9, 7.9 Hz).

Reference Example 122-[4-(6-Fluoropyridin-2-yl)piperidin-1-yl]ethylamine trihydrochloride

According to the method of Reference examples 9-11, the title compoundwas prepared from 2-bromo-6-fluoropyridine.

¹H-NMR (400 MHz, DMSO-d₆) δ: 2.02-2.19 (4H, m), 2.91-3.06 (1H, m),3.11-3.21 (2H, m), 3.31-3.44 (4H, m), 3.66 (2H, d, J=12.2 Hz), 7.05 (1H,dd, J=8.1, 2.7 Hz), 7.27 (1H, dd, J=7.4, 2.6 Hz), 7.97 (1H, dd, J=8.1,8.1 Hz), 8.54 (3H, s), 11.04 (1H, s).

Reference Example 132-[4-(6-Methoxypyridin-2-yl)piperidin-1-yl]ethylamine trihydrochloride

According to the method of Reference examples 9-11, the title compoundwas prepared from 2-bromo-6-methoxypyridine.

¹H-NMR (300 MHz, D₂O) δ: 1.93-2.14 (2H, m), 2.19-2.33 (2H, m), 3.05-3.33(3H, m), 3.39-3.55 (4H, m), 3.69-3.80 (2H, m), 4.02 (3H, s), 7.16 (2H,dd, J=15.3, 8.2 Hz), 8.13 (1H, d, J=8.7, 7.6 Hz).

Reference Example 142-{4-[6-(Difluoromethyl)pyridin-2-yl]piperidin-1-yl}ethylaminetrihydrochloride

According to the method of Reference examples 9-11, the title compoundwas prepared from 2-bromo-6-difluoromethylpyridine.

¹H-NMR (300 MHz, D₂O) δ: 1.78-1.92 (2H, m), 1.91-2.10 (2H, m), 2.63 (2H,t, J=12.1 Hz), 2.83-3.02 (3H, m), 3.09-3.33 (4H, m), 6.71 (1H, t, J=55.0Hz), 7.41-7.50 (1H, m), 7.53 (1H, d, J=7.6 Hz), 7.86-7.96 (1H, m).

Reference Example 15N-(2-{4-[(6E)-6-Hydrazinylidene-1,6-dihydropyridin-2-yl]piperidin-1-yl}ethyl)-tetrahydro-2H-pyran-4-carboxamide

To a solution of the compound of Example 32 (300 mg) in 1,4-dioxane (2.0mL) was added 50-60% aqueous hydrazine (2.9 mL), and the reactionmixture was stirred at 100° C. for 24 hours. The reaction mixture wasconcentrated, and dichloromethane (10 mL) was added thereto. The mixturewas washed with brine (10 mL×2), and concentrated. The residue waspurified by silica gel column chromatography (dichloromethane/methanol)to give the title compound (270 mg).

¹H-NMR (300 MHz, CDCl₃) δ: 1.63-1.90 (6H, m), 1.90-2.00 (2H, m), 2.14(2H, td, J=11.7, 2.6 Hz), 2.39 (1H, tt, J=10.4, 5.3 Hz), 2.47-2.65 (3H,m), 2.91-3.06 (2H, m), 3.28-3.52 (4H, m), 4.05 (2H, td, J=11.5, 3.6 Hz),5.74 (1H, s), 6.22 (1H, s), 6.52-6.62 (2H, m), 7.46 (1H, dd, J=8.2, 7.4Hz).

Test 1: Evaluation of Agonistic Activity for Human 5-HT_(1A) Receptorand Human D₄ Receptor

Aequorin, Ga16 proteins, and each receptor were transiently expressed inCHO-K1 cell (Chinese hamster ovary), and seeded to 384-well plate. Theplate was incubated in a CO₂ incubator at 37° C. for 24 hours. Eachexample compound dissolved in DMSO was added thereto, and the change ofluminescence amount was measured with Hamamatsu FDSS/μCELL System(Hamamatsu Photonics). As for the agonistic activity, the maximumactivity (E_(max)) of each compound was calculated on the assumptionthat the luminescence amount of the well without the compound is 0% andthe luminescence amount of the well containing 10 μmol/L endogenousligand is 100%. The results are shown in the table below.

5-HT_(1A) agonistic activity D₄ agonistic activity EC₅₀ Emax EC₅₀ EmaxExample (nmol/L) (%) (nmol/L) (%) 1 <10 96 11.9 67 2 323 86 58.9 61 3 3885 33.5 76 4 <10 90 25.1 71 5 42 100 55.8 57 6 44 96 <10 58 7 <10 106<10 58 8 <10 71 37.1 65 9 <10 84 <10 53 10 10 90 10 85 11 82 92 30.8 5612 <10 43 35 52 13 <10 48 <10 55 14 <10 41 <10 53 15 100 33 41 55 16 4336 31 51 17 94 30 44 51 18 68 43 37 61 19 <10 65 9 84 20 57 40 15 60 2184 30 65 62 22 595 25 57 57 23 632 28 62 59 24 67 50 32 62 25 67 46 3049 26 395 43 3389 36 27 570 44 1648 51 28 47 69 37 44 29 <10 50 24 74 3027 36 <10 59 31 35 40 <10 52 32 67 51 7 67 33 22 83 13 62 34 22 42 15 5535 525 27 64 52 36 279 38 31 58 37 343 40 52 57 38 86 50 42 35

Test 2: Evaluation of Binding Activity to Human 5-HT_(1A) Receptor,Human D₄ Receptor, and Human D₂ Receptor

The binding affinity of the present compounds to human 5-HT_(1A)receptor, human D₄ receptor, and human D₂ receptor was measured in amanner mentioned below.

CHO cell membrane fraction in which human 5-HT_(1A) receptor, human D₄receptor, and human D₂ receptor were expressed was purchased fromPerkinElmer Co., Ltd. In the evaluation test of binding, the testcompound dissolved in DMSO, each receptor membrane preparation dilutedwith buffer solution, and [3H] 8-OH-DPAT (for 5-HT_(1A) receptor), [3H]dopamine (for D₄ receptor), or [3H] spiperone (for D₂ receptor) (allwere obtained from PerkinElmer Co., Ltd.) were mixed, and each mixturewas incubated at room temperature for 30 or 60 minutes. The nonspecificbinding to each receptor was evaluated by a competition bindingexperiment in the presence of 10 μmol/L 8-OH-DPAT, 10 μmol/L dopamine,or 10 μmol/L spiperone, respectively. The radioactivity of eachreceptor-binding sample was measured with a liquid scintillation counter(PerkinElmer Co., Ltd.), the 50% inhibitory concentration wascalculated, and Ki value was evaluated based on the dissociationconstant and the substrate concentration caluculated in the saturatedbond test, which was used as binding affinity. The results are shown inthe table below.

Example 5-HT_(1A) (nmol/L) D₄ (nmol/L) D₂ (nmol/L) 1 0.4 11 1144 2 11109 >10000 3 7.1 198 >10000 4 0.4 26 >10000 5 80 170 >10000 6 37101 >10000 7 13 43 >10000 8 1.4 111 >10000 9 1.1 8.0 2443 10 1.419 >10000 11 2.1 44 >10000 12 0.2 4.5 357 13 1.1 24 >10000 14 0.1 3.02438 15 13 505 >10000 16 6 27 1688 17 26 91 >10000 18 21 19 2209 19 0.88 >10000 20 6.8 92 >10000 21 15 201 2170 22 58 2241 >10000 23 166408 >10000 24 27 3378 >10000 25 20 423 3327 26 79 1902 >10000 27 772474 >10000 28 28 104 2472 29 0.4 22 >10000 30 1.4 14 >10000 31 0.3 2.91280 32 42 96 >10000 33 21 119 >10000 34 10 56 >10000 35 278 2258 >1000036 132 120 >10000 37 108 73 >10000 38 37 10 >10000

Test 3-1: Metabolic Stability Test of Human Liver Microsome

The stability of the present compounds for human liver microsomemetabolism was evaluated as mentioned below. The used human livermicrosome was obtained from Xenontech. Human liver microsome, NADPH, andeach test compound were mixed in 25 mmol/L phosphate buffer solution (pH7.4) to adjust each concentration as shown below, and the mixture wasincubated at 37° C. for 30 minutes.

-   -   human liver microsome: 0.1 mg/mL    -   NAPDH: 3.2 mmol/L    -   test compound: 0.1 μmol/L

The residual ratio of the test compound in each sample after theincubation for 30 minutes was measured with a LC-MS, and the metabolicstability of human liver microsome was calculated about each testcompound with the following formula.

Metabolic stability of human liver microsome(mL/min/mgprotein)=−LN(residual ratio)/“reaction time”/“concentration of humanliver microsome”

The results are shown in the table below.

Metabolic stability of human liver Example microsome (mL/min/mg protein)1 0.073 2 0.069 3 <0.01 4 <0.01 5 <0.01 6 <0.01 7 0.017 8 0.017 9 0.02510 0.015 11 <0.01 12 0.115 13 <0.05 14 0.084 15 <0.05 16 <0.05 18 <0.0520 <0.05 21 <0.05 25 <0.05 28 <0.05 29 <0.05 30 0.114 31 <0.05 33 <0.0534 <0.05 38 <0.05

Test 3-2: Metabolic Stability Test of Human Liver Microsome

In order to evaluate the metabolic stability of human liver microsomesmore precisely, the stability of the present compounds for human livermicrosome metabolism was evaluated with a suitable concentration ofhuman liver microsome, as mentioned below. The used human livermicrosome was obtained from Xenontech. Human liver microsome, NADPH, andeach test compound were mixed in 25 mmol/L phosphate buffer solution (pH7.4) to adjust each concentration as shown below, and the mixture wasincubated at 37° C. for 30 minutes.

-   -   human liver microsome: 0.5 or 1.0 mg/mL    -   NAPDH: 3.2 mmol/L    -   test compound: 0.1 μmol/L

The residual ratio of the test compound in each sample after theincubation for 30 minutes was measured with a LC-MS, and the metabolicstability of human liver microsome was calculated about each testcompound with the following formula.

Metabolic stability of human liver microsome(mL/min/mgprotein)=−LN(residual ratio)/“reaction time”/“concentration of humanliver microsome”

The results are shown in the table below.

Metabolic stability of human liver Example microsome (mL/min/mg protein)1 0.031 8 0.023 9 0.016 11 0.0075

Test 4-1: Predictive Test of Human Half-Life

The disappearance half-life of the present compounds in human waspredicted in a manner mentioned below. 0.01 mol/L of the presentcompound in aqueous hydrochloric acid solution was parenterallyadministered to cynomolgus monkey. 5 minutes, 15 minutes, 30 minutes, 1hour, 2 hours, 4 hours, 6 hours, and 24 hours after the administration,the blood was collected. The plasma was obtained from the collectedblood, the drug concentration in the plasma was measured with a LC-MS,and the monkey distribution volume was calculated from the transition ofthe concentrations. The unbound fraction rate of the present compound inserum of human and monkey was measured by equilibrium dialysis method.

Using the monkey distribution volume, the unbound fraction rate in serumof human and monkey, and the result of the metabolic stability of humanliver microsome which was obtained in Test 3-1, the half-life in humanwas calculated according to the formula below.

“Human distribution volume”=“monkey distribution volume”×“unboundfraction rate in serum of human”/“unbound fraction rate in serum ofmonkey”

“Human hepatic clearance”=(“human hepatic blood flow”×“unbound fractionrate in serum of human”×56.7×“metabolic stability of human livermicrosome”)/(“human hepatic blood flow”+“unbound fraction rate in serumof human”×56.7×“metabolic stability of human liver microsome”)

“Half-life in human”=0.693×“human distribution volume”/“human hepaticclearance”

The results are shown in the table below.

Example Half-life in human (h) 1 11 8 9.2 11 13

Test 4-2: Predictive Test of Human Half-Life

In order to estimate the disappearance half-life of the presentcompounds in human more precisely, the half life was predicted by usingthe result of the metabolic stability of human liver microsome which wasobtained in Test 3-2, in a manner mentioned below.

0.01 mol/L of the present compound in aqueous hydrochloric acid solutionwas parenterally administered to cynomolgus monkey. 5 minutes, 15minutes, 30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, and 24 hoursafter the administration, the blood was collected. The plasma wasobtained from the collected blood, the drug concentration in the plasmawas measured with a LC-MS, and the monkey distribution volume wascalculated from the transition of the concentrations. The unboundfraction rate of the present compound in serum of human and monkey wasmeasured by equilibrium dialysis method.

Using the monkey distribution volume, the unbound fraction rate in serumof human and monkey, and the result of the metabolic stability of humanliver microsome which was obtained in Test 3-2, the half-life in humanwas calculated according to the formula below.

“Human distribution volume”=“monkey distribution volume”×“unboundfraction rate in serum of human”/“unbound fraction rate in serum ofmonkey”

“Human hepatic clearance”=(“human hepatic blood flow”×“unbound fractionrate in serum of human”×56.7×“metabolic stability of human livermicrosome”)/(“human hepatic blood flow”+“unbound fraction rate in serumof human”×56.7×“metabolic stability of human liver microsome”)

“Half-life in human”=0.693×“human distribution volume”/“human hepaticclearance”

The results are shown in the table below.

Example Half-life in human (h) 1 24 8 59 11 17 9 10

Test 5-1: Evaluation of Activity for Inhibiting hERG Channel

The activity of the present compound for inhibiting hERG channel wasmeasured by whole-cell patch clamp method with auto patch clamp system,using CHO cell wherein hERG channel involved in human rapidly activatingdelayed rectifier potassium current (I_(Kr)) was forcibly expressed.

(Preparation of Cell Suspension)

hERG-CHO cell purchased from ChanTest was incubated at 37° C. in a CO₂incubator, and the cell was exfoliated from the flask with trypsin toprepare a cell suspension, shortly before the hERG current measurement.

(Preparation of Solution)

The extracellular fluid and intracellular fluid which were used in themeasurement were prepared as follows.

Extracellular fluid: 2 mmol/L CaCl₂), 1 mmol/L MgCl₂, 10 mmol/L HEPES, 4mmol/L KCl, 145 mmol/L NaCl, 10 mmol/L glucose Intracellular fluid: 5.4mmol/L CaCl₂), 1.8 mmol/L MgCl₂, 10 mmol/L HEPES, 31 mmol/L KOH, 10mmol/L EGTA, 120 mmol/L KCl, 4 mmol/L Na₂-ATP

Test compound solution: The test compound was dissolved in DMSO byadjusting the concentration to 2 mmol/L or 20 mmol/L to prepare eachtest compound solution. Further, the test compound solution was dilutedwith the extracellular fluid by 200-fold, which was serially dilutedwith the extracellular fluid to prepare each concentration of the testcompound solution which is used to calculate IC₅₀ value of hERGinhibition.

(Measurement of Current Value and Data Analysis)

The cell suspension, the extracellular fluid, the intracellular fluid,and the measurement plate were set in an auto patch clamp system, andthe hERG current was measured by whole-cell patch clamp method. Thevoltage-protocol was as follows: the holding potential was adjusted to−80 mV, the depolarizing pulse was added at −50 mV to +20 mV for 5seconds, the repolarizing pulse was added at −50 mV for 5 seconds, thenthe potential was returned to the holding potential. Each pulse intervalwas 15 seconds. The data analysis was carried out with Qpatch AssaySoftware (Biolin Scientific). The test was carried out applyingincrescently 4 concentrations of each test compound, and the average ofthe peak tail currents that were obtained by the last 3 stimulations ineach applied concentration was determined to be the evaluated data. Byusing the current inhibition rate for the pre-applied current at eachconcentration of each test compound, IC₅₀ value was calculated by Hillequation with the software.

The results are shown in the table below.

Example hERG inhibition IC₅₀ (μmol/L) 1 2.5 2 >10 3 32.1 4 4.0 5 48.2 612.8 7 5.6 8 44.3 9 5.9 10 >10 11 12.7

Test 5-2: Evaluation of Activity for Inhibiting hERG Channel

The activity of the present compound for inhibiting hERG channel wasmeasured by whole-cell patch clamp method with auto patch clamp system,using CHO cell wherein hERG channel involved in human rapidly activatingdelayed rectifier potassium current (I_(Kr)) was forcibly expressed.

(Preparation of Cell Suspension)

hERG-CHO cell purchased from ChanTest was incubated at 37° C. in a CO₂incubator, and the cell was exfoliated from the flask with trypsin toprepare a cell suspension, shortly before the hERG current measurement.

(Preparation of Solution)

The extracellular fluid and intracellular fluid which were used in themeasurement were prepared as follows.

Extracellular fluid: 2 mmol/L CaCl₂), 1 mmol/L MgCl₂, 10 mmol/L HEPES, 4mmol/L KCl, 145 mmol/L NaCl, 10 mmol/L glucose

Intracellular fluid: 10 mmol/L HEPES, 10 mmol/L EGTA, 20 mmol/L KCl, 130mmol/L KF

Test compound solution: The compound was dissolved in DMSO by adjustingthe concentration to 2 mmol/L or 20 mmol/L to prepare each test compoundsolution. Further, the test compound solution was diluted with theextracellular fluid by 200-fold, which was serially diluted with theextracellular fluid to prepare each concentration of the test compoundsolution which is used to calculate IC₅₀ value of hERG inhibition.

(Measurement of Current Value and Data Analysis)

The cell suspension, the extracellular fluid, the intracellular fluid,and the measurement plate were set in an auto patch clamp system, andthe hERG current was measured by whole-cell patch clamp method. Thevoltage-protocol was as follows: the holding potential was adjusted to−80 mV, the depolarizing pulse was added at −50 mV to +20 mV for 5seconds, the repolarizing pulse was added at −50 mV for 5 seconds, thenthe potential was returned to the holding potential. Each pulse intervalwas 15 seconds. The data analysis was carried out with Qube AssaySoftware (Sophion Scientific). The test was carried out applyingincrescently 4 concentrations of each test compound, and the average ofthe peak tail currents that were obtained by the last 3 stimulations ineach applied concentration was made to be the evaluated data. By usingthe current inhibition rate for the pre-applied current at eachconcentration of each test compound, IC₅₀ value was calculated by Hillequation with the software.

The results are shown in the table below.

Example hERG inhibition IC₅₀ (μmol/L) 12 3.5 13 >10 14 8.1 15 >10 16 >1018 >10 20 >10 21 >10 25 >10 28 >10 29 >10 30 >10 31 >10 33 >10 34 5.5 38>10

Test 6: Contextual Fear Conditioning Test

The antianxiety of the present compounds was evaluated in a mannermentioned below.

The evaluation of an 8-week-old SD male rat with a fear conditioningtest system (O'HARA & CO., LTD.) was carried out in 2-day test schedule.On the 1st day of the test, by giving 0.5 mA of electric shock to therat as unconditioned stimulus 5 times for 6 minutes, the rat was made tolearn the relationship the context (the illuminance in the cage: 200 1×)which was given as conditioned stimulus, and phobic stimulus. On the 2ndday, the present compound was subcutaneously administered with salinesolution to the rat, or orally administered with methylcellulosesuspension to the rat. 0.5 or 1 hour after the administration, the ratwas made to softly enter the cage under the condition in which theunconditioned stimulus was not given in the context. The time ofcataleptic freezing reaction that the rat took for 5-minutefreely-moving period and its ratio were measured. The ratios ofcataleptic freezing reaction between the solvent-administration groupand the present compound-administration group were compared to bestatistically processed. The compound-administration groups of Example 1(15 mg/kg administration), Example 8 (10 mg/kg administration), andExample 11 (30 mg/kg administration) showed 82.5%, 41.0%, and 65.5%decreases of the cataleptic freezing reaction for thesolvent-administration group, respectively (see, FIG. 1).

Test 7: Marble-Burying Behavior Test

The effect of the present compound for obsessive-compulsivedisorder-like behavior was evaluated in a manner mentioned below.

450-500 g of paper floorcloth was beded in a plastic cage (floor area:778 cm²), and 20 glass marbles were set on the paper floorcloth atregular intervals. To a 5-week-old ICR male mouse, the present compoundwas intraperitoneally administered with saline solution. 15 minutesafter the administration, the mouse was made to softly enter the cornerof the cage and move freely in the cage for 15 minutes. Then the mousewas taken out from the cage. The number of the marbles that were buriedin the floorcloth was counted. The numbers in the solvent-administrationgroup and the present compound-administration group were compared to bestatistically processed. The compound-administration groups of Example 1(0.5 mg/kg administration) and Example 11 (2 mg/kg administration)showed 44.8% and 64.8% decreases of the buried marbles in the floorclothfor the solvent-administration group, respectively (see, FIG. 2).

In addition, compared with the result of single administration ofescitalopram which is a typical selective serotonin reuptake inhibitor,the combination of escitalopram and the present compound of Example 1(0.3 mg/kg administration) or Example 11 (1 mg/kg administration) showedsignificant enhancement effect of decreasing the number of the buriedmarbles (43.8%, 42.9%) (see, FIG. 3)

Test 8: Forced Swimming Test

The antidepressive effect of the present compound was evaluated in amanner mentioned below.

The test was carried out with 8-week-old Wistar male rat in 4-day testschedule. On the 1st day of the test, the rat was put into a transparentplastic bath filled with 5.8 L of tap water at 25° C., and made to swimfor 15 minutes as swimming training. After the swimming training, therat was rapidly wiped to remove the attached waterdrop, and returned tothe home cage. 15 minutes after the training, the present compound or apositive control compound was orally administered with methylcellulosesuspension to the rat. On the next day of the training and the day afternext, the present compound or the positive control compound was orallyadministered with methylcellulose suspension to the rat once a day. Onthe 4th day, the swimming test was carried out. On the day of theswimming test, the present compound or the positive control compound wasorally administered with methylcellulose suspension to the rat one hourbefore the start of the test. The swimming test was carried out with therat in the above-mentioned water bath for 5 minutes. The swimmingmovement of the individual was recorded with a video from the side ofthe water bath, and the immobility time was measured with a stop-watch.The immobility used herein means a state that the animal is floating inthe water bath without moving the forelimbs and torso, and it was judgedthat insensible movement for keeping its floating pose was immobility.The accumulated time of immobility was defined as immobility time forthe individual. The immobility times of the solvent-administration groupand the present compound-administration group were compared to bestatistically processed. The compound-administration groups of Example 1(5 mg/kg administration) and Example 11 (10 mg/kg administration) showed74.7% and 59.2% decreases of the immobility time for thesolvent-administration group, respectively (see, FIG. 4).

Test 9: Microdialysis Test

The effect of the present compound for the release amount ofintracerebral monoamine was evaluated in a manner mentioned below.

8-Week-old Wistar male rat was fixed on a brain stereotaxic apparatusunder anesthesia. The scalp was incised, the subcutaneous tissue wasremoved, the position of the bregma was measured, and the installationposition of a guide cannula was calculated (the position of theorbitofrontal cortex which defined according to the brain stereotaxiccoordinates of Paxinos & Watson (2.0 mm right, 4.2 mm anterior frombregma)). The skull was drilled with a dental drill at the installationposition of the guide cannula, and an anchor screw was set about 1 cmposterior to the hole. The guide cannula was set and fixed with a dentalcement, and then the scalp was sutured. The animal was released from thebrain stereotaxic apparatus, and was moved back to the breeding cage. Inthe event of the test, the rat was put in an acrylic observable cage,and a dialysis probe was inserted along the guide cannula to connect toa free-moving tube. With an infusion pump, Ringer solution was perfusedat 2 μL/min, and the dialysis solution was recovered at 20-minuteintervals. After 3 samples from the 1st recovery were recovered, thepresent compound was orally administered with methylcellulose suspensionto the rat. Until 180 minutes after the administration, the dialysissolutions were recovered (9 samples). The recovered dialysis solutionswere analyzed with a HPLC-ECD system to determine the contents ofnorepinephrine (NE), dopamine (DA), and serotonin (5-HT). The compoundgroup of Example 11 (10 mg/kg administration) showed a decrese of theserotonin content in the dialysis solution (20.6%) and increases of thenorepinephrine and dopamine contents in the dialysis solution (18.3%,12.4%), compared with the solvent-administration group. In addition, thecombination administration of sertraline and Example 11 (10 mg/kgadministration) showed significant increases of norepinephrine anddopamine in the dialysis solution (100%, 119%), compared with the resultof the single administration of sertraline (see, FIG. 5).

It is known that the single administration of a serotonin 5-HT_(1A)agonist can decrease the serotonin content. On the other hand, when aserotonin 5-HT_(1A) agonist is repetitively administered, thesensitivity of the autoreceptor can lower to deactivate the inhibitionof the serotonin release. Thus, it is thought that the antidepressiveeffect can be exerted (Neuroscience. 1999, 93(4): 1251-1262, NeurochemInt. 2002, 40(4): 355-360). Example 11 did not decrease the serotonincontent in the combination administration with sertraline or in singleadministration. Considering the results, the present compound isexpected to exert the potentiation of antidepressive effect through thecombination administration with sertraline, which is very different fromother serotonin 5-HT_(1A) agonists.

INDUSTRIAL APPLICABILITY

The present compound has dual agonism for serotonin 5-HT_(1A) receptorand dopamine D₄ receptor, and thereby the present compound is useful asa medicament for treating symptoms in anxiety-related disorder.

1. A compound of formula (1):

or a pharmaceutically acceptable salt thereof, wherein R¹ isoptionally-substituted C₁₋₆ alkyl, optionally-substituted C₃₋₁₀cycloalkyl, or optionally-substituted 5- to 10-membered saturated orpartially-unsaturated heterocyclyl group; R² is halogen atom, cyano,C₁₋₆ alkyl which may be optionally substituted with 1 to 3 the same ordifferent halogen atoms, C₁₋₆ alkoxy which may be optionally substitutedwith 1 to 3 the same or different halogen atoms, or amino which may beoptionally substituted with 1 or 2 the same or different C₁₋₆ alkylgroups; and the bond accompanied with broken line is single bond ordouble bond.
 2. The compound of claim 1 or a pharmaceutically acceptablesalt thereof, wherein R¹ is (1) C₁₋₆ alkyl which may be optionallysubstituted with 1 to 3 the same or different substituents selected fromthe group consisting of halogen atom, hydroxy, C₃₋₇ cycloalkyl, and C₁₋₆alkoxy, (2) C₃₋₁₀ cycloalkyl which may be optionally substituted with 1to 4 the same or different substituents selected from the groupconsisting of halogen atom, hydroxy, cyano, C₁₋₆ alkyl which may beoptionally substituted with 1 to 3 the same or different halogen atom orC₁₋₆ alkoxy, C₁₋₆ alkoxy which may be optionally substituted with 1 to 3the same or different halogen atom or C₁₋₆ alkoxy, and amino which maybe optionally substituted with 1 or 2 the same or different C₁₋₆ alkyl,or (3) 5- to 10-membered saturated or partially-unsaturated heterocyclylgroup which may be optionally substituted with 1 to 4 the same ordifferent substituents selected from the group consisting of halogenatom, hydroxy, cyano, C₁₋₆ alkyl which may be optionally substitutedwith 1 to 3 the same or different halogen atom or C₁₋₆ alkoxy, C₁₋₆alkoxy which may be optionally substituted with 1 to 3 the same ordifferent halogen atom or C₁₋₆ alkoxy, and amino which may be optionallysubstituted with 1 or 2 the same or different C₁₋₆ alkyl.
 3. Thecompound of claim 1, or a pharmaceutically acceptable salt thereof,wherein R¹ is (1) C₃₋₇ cycloalkyl which may be optionally substitutedwith 1 to 4 the same or different substituents selected from the groupconsisting of halogen atom, and C₁₋₆ alkyl which may be optionallysubstituted with 1 to 3 the same or different halogen atom or C₁₋₆alkoxy, or (2) 5- or 6-membered saturated or partially-unsaturatedheterocyclyl group which may be optionally substituted with 1 to 4 thesame or different substituents selected from the group consisting ofhalogen atom, and C₁₋₆ alkyl which may be optionally substituted with 1to 3 the same or different halogen atom or C₁₋₆ alkoxy.
 4. The compoundof claim 1, or a pharmaceutically acceptable salt thereof, wherein R¹ isC₃₋₇ cycloalkyl which may be optionally substituted with 1 to 4 fluorineatoms, or 5- or 6-membered saturated or partially-unsaturatedheterocyclyl group which may be optionally substituted with 1 to 4fluorine atoms.
 5. The compound of claim 1, or a pharmaceuticallyacceptable salt thereof, wherein R¹ is cyclohexyl which may beoptionally substituted with 1 to 4 fluorine atoms, tetrahydropyranyl,tetrahydrofuryl, dihydropyranyl, or dihydrofuryl.
 6. The compound ofclaim 1, or a pharmaceutically acceptable salt thereof, wherein R¹ isdifluorocyclohexyl, or tetrahydropyranyl.
 7. The compound of claim 1, ora pharmaceutically acceptable salt thereof, wherein R² is halogen atom,or C₁₋₆ alkyl which may be optionally substituted with 1 to 3 the sameor different halogen atoms.
 8. The compound of claim 1, or apharmaceutically acceptable salt thereof, wherein R² is C₁₋₄ alkyl whichmay be optionally substituted with 1 to 3 fluorine atoms.
 9. Thecompound of claim 1, or a pharmaceutically acceptable salt thereof,wherein the bond accompanied with broken line is single bond.
 10. Thecompound of claim 1 selected from the following compounds, or apharmaceutically acceptable salt thereof,4,4-difluoro-N-(2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)cyclohexane-carboxamide,N-{2-[4-(6-methylpyridin-2-yl)piperidin-1-yl]ethyl}-tetrahydro-2H-pyran-4-carboxamide,2,2-dimethyl-N-(2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)propanamide,andN-(2-(4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl)ethyl)-tetrahydro-2H-pyran-4-carboxamide.11. The compound of claim 1 selected from the following compounds, or apharmaceutically acceptable salt thereof,4,4-difluoro-N-(2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)cyclohexane-carboxamide,N-{2-[4-(6-methylpyridin-2-yl)piperidin-1-yl]ethyl}-tetrahydro-2H-pyran-4-carboxamide,andN-(2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)-tetrahydro-2H-pyran-4-carboxamide.12. The compound of claim 1 of the following compound, or apharmaceutically acceptable salt thereof,4,4-difluoro-N-(2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)cyclohexane-carboxamide.13. The compound of claim 1 of the following compound, or apharmaceutically acceptable salt thereof,N-{2-[4-(6-methylpyridin-2-yl)piperidin-1-yl]ethyl}-tetrahydro-2H-pyran-4-carboxamide.14. The compound of claim 1 of the following compound, or apharmaceutically acceptable salt thereof,2,2-dimethyl-N-(2-(4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-ylethyl)propanamide.
 15. The compound of claim 1 of the followingcompound, or a pharmaceutically acceptable salt thereof,N-(2-{4-[6-(trifluoromethyl)pyridin-2-yl]piperidin-1-yl}ethyl)-tetrahydro-2H-pyran-4-carboxamide.16. A medicament comprising the compound of claim 1 or apharmaceutically acceptable salt thereof as an active ingredient.
 17. Amedicament for treating generalized anxiety disorder, major depression,obsessive-compulsive disorder, Parkinson's disease, Rett syndrome,attention-deficit hyperactivity disorder, autism spectrum disorder, ordementia, comprising the compound of claim 1 or a pharmaceuticallyacceptable salt thereof as an active ingredient.
 18. A method fortreating generalized anxiety disorder, major depression,obsessive-compulsive disorder, Parkinson's disease, Rett syndrome,attention-deficit hyperactivity disorder, autism spectrum disorder, ordementia, comprising administering a therapeutically effective amount ofthe compound of claim 1 or a pharmaceutically acceptable salt thereof toa patient in need thereof.
 19. Use of the compound of claim 1 or apharmaceutically acceptable salt thereof, in the preparation of amedicament for treating generalized anxiety disorder, major depression,obsessive-compulsive disorder, Parkinson's disease, Rett syndrome,attention-deficit hyperactivity disorder, autism spectrum disorder, ordementia.
 20. The compound of claim 1 or a pharmaceutically acceptablesalt thereof, for use in the treatment of generalized anxiety disorder,major depression, obsessive-compulsive disorder, Parkinson's disease,Rett syndrome, attention-deficit hyperactivity disorder, autism spectrumdisorder, or dementia.
 21. A medicament comprising the compound of claim1 or a pharmaceutically acceptable salt thereof, and at least one othermedicament selected from drugs classified as an antianxiety drug or anantidepressant drug.
 22. A medicament for treating generalized anxietydisorder, major depression, obsessive-compulsive disorder, Parkinson'sdisease, Rett syndrome, attention-deficit hyperactivity disorder, autismspectrum disorder, or dementia, comprising the compound of claim 1 or apharmaceutically acceptable salt thereof, which is used in combinationwith at least one other medicament selected from drugs classified as anantianxiety drug or an antidepressant drug.
 23. The medicament of claim21, wherein the antianxiety drug is a selective serotonin reuptakeinhibitor.
 24. The medicament of claim 23, wherein the selectiveserotonin reuptake inhibitor is at least one drug selected from thegroup consisting of sertraline, escitalopram, fluvoxamine, fuoxetine,paroxetine, clomipramine, and pharmaceutically acceptable salts thereof.25. The medicament of claim 21, wherein the antidepressant drug is aserotonin reuptake inhibitor.
 26. The medicament of claim 25, whereinthe serotonin reuptake inhibitor is at least one drug selected from thegroup consisting of milnacipran, duloxetine, venlafaxine, amoxapine,clomipramine, nortriptyline, imipramine, vortioxetine, andpharmaceutically acceptable salts thereof.